Title:
LIBERTY CUT GEMSTONE
Kind Code:
A1


Abstract:
A cut gemstone comprising a girdle, a crown above the girdle and a pavilion below the girdle, the crown comprising a table and the pavilion comprising a culet and a plurality of pavilion faces between the girdle and the culet, the pavilion faces comprising a plurality of constituent faces and a plurality of star faces, the star faces and constituent faces alternating in circumferential direction of the pavilion, each of the constituent faces having a first and a second cutting edge, each star face being delimited from adjacent first and second constituent faces by respectively the first and second cutting edge of the first and second constituent faces respectively, each first cutting edge of a constituent face intersecting with a second cutting edge of a consecutive constituent face thus defining first and second star points respectively, the first and second cutting edges of consecutive constituent faces diverging towards the culet causing the first and second cutting edges of one single constituent face to intersect in a top of the constituent face, the star faces thus defining a visible star-shaped figure between them, the star-shaped figure comprising the culet. The cut gemstone according to the invention has an enhanced brilliance, contrast, fire and scintillation by adding specific facets in the pavilion.



Inventors:
Webb, Mark (Spokane, WA, US)
Application Number:
11/382375
Publication Date:
11/15/2007
Filing Date:
05/09/2006
Primary Class:
International Classes:
A44C17/00
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Related US Applications:



Primary Examiner:
LAVINDER, JACK W
Attorney, Agent or Firm:
Nixon Peabody LLP (San Francisco, CA, US)
Claims:
1. A cut gemstone comprising a girdle, a crown above the girdle and a pavilion below the girdle, the crown comprising a table and the pavilion comprising a culet and a plurality of pavilion faces between the girdle and the culet, the pavilion faces comprising a plurality of constituent faces and a plurality of star faces, the star faces and constituent faces alternating in circumferential direction of the pavilion, each of the constituent faces having a first and a second cutting edge, each star face being delimited from adjacent first and second constituent faces by respectively the first and second cutting edge of the first and second constituent faces respectively, each first cutting edge of a constituent face intersecting with a second cutting edge of a consecutive constituent face thus defining first and second star points respectively, the first and second cutting edges of consecutive constituent faces diverging towards the culet causing the first and second cutting edges of one single constituent face to intersect in a top of the constituent face, the star faces thus defining a visible star-shaped figure between them, the star-shaped figure comprising the culet, characterised in that each constituent face comprises a third cutting edge extending from the top towards the girdle, a fourth and a fifth cutting edge extending from the first and second star point towards the third cuffing edge, the third, fourth and fifth cutting edge converging into a single first intersection point, the first and the fourth cutting edges defining within the constituent face a first star delimiting facet along a first side of the third cutting edge, the second and fifth cutting edge defining with the constituent face a second star delimiting facet along a second side of the third cutting edge opposite the first star delimiting facet, the fourth and fifth cutting edges defining circumferential facets on a first side of a first striping cutting edge, the first striping cutting edges extending between adjacent first and second star points, a striping facet extending along a second side of the first striping cutting edge opposite the circumferential facet, the striping facets comprising a second striping cutting edge extending from a first star point towards the girdle and a third striping cutting edge extending from a second star point towards the girdle, thus forming concatenated striping facets over the circumference of the pavilion.

2. The cut gemstone according to claim 1, characterised in that the first star delimiting facet comprises at least one first emphasizing cutting edge which extends from the first star point and in that second star delimiting facet comprises at least one second emphasizing cutting edge which extends from the second star point 10, the first and second emphasizing cutting edges converging to each other and intersecting with the third cutting edge at a second intersection point.

3. The cut gemstone according to claim 2, characterised in that each first and second star delimiting facet comprises two emphasizing cutting edges.

4. The cut gemstone according to claim 1, characterised in that the first striping edges form a regular polygon.

5. The cut gemstone according to claim 1, characterised in that the constituent faces are congruent.

6. The cut gemstone according to claim 1, characterised in that the star delimiting facets are congruent.

7. The cut gemstone according to claim 1, characterised in that the star faces are congruent.

8. The cut gemstone according to claim 1, characterised in that the striping facets are congruent.

9. The cut gemstone according to claim 1, characterised in that the second and third striping cutting edges are of substantially equal length.

10. The cut gemstone according to claim 1, characterised in that the pavilion comprises a first axis of symmetry which extends from the culet to the table, having a first symmetry number, and in that the axis of symmetry comprises the culet.

11. The cut gemstone according to claim 10, characterised in that the first symmetry number of the first axis of symmetry equals the number of star points.

12. The cut gemstone according to claim 10, characterised in that the crown comprises a second axis of symmetry which corresponds to the first axis of symmetry of the pavilion.

13. The cut gemstone according to claim 10, characterised in that the table is a regular polygon delimited by a number of table cutting edges equal to the first symmetry number, the cutting edges of the polygon intersecting in respective corners of the polygon.

14. The cut gemstone according to claim 13, characterised in that, when looking through the crown towards the culet, star points lie on a line connecting the intersection of the first axis of symmetry with the table with the corners of the polygon forming the table.

15. The cut gemstone according to claim 10, characterised in that the first symmetry number is three, four, five, six, seven eight or more.

Description:

BACKGROUND OF THE INVENTION

The value of gemstones, in particular of gemstones like diamonds, is generally estimated by four determining characteristics, known to the person skilled in the art as: carat, clarity, colour and cut. A common cut is known as the “brilliant cut”, which is a round-shaped cut. The brilliant cut has 58 facets: the table, the culet, 32 crown facets between the table and the girdle and 24 pavilion facets between the girdle and the culet. All the facets are arranged round an eight-fold symmetry axis extending from the culet towards the centre of symmetry of the table. When looking through the table towards the culet a great amount of incident light is internally reflected to a spectator looking through the cut gemstone towards the culet, this effect is known to the person skilled in the art as the brilliance of the stone. When looking through the table towards the culet, no image of a star is reflected towards the spectator.

In another round-shaped cut known as the “Lone Star Cut” the pavilion comprises a five-pointed symmetrical star, in the form of a pentagram, which represents the public symbol of The State of Texas. Thereto the pavilion of the cut comprises five star faces extending from the culet towards the girdle. Each star face is subdivided into two longitudinal facets by a cutting edge connecting each star point with the culet. The star faces are surrounded by several other facets. When looking through the table towards the culet, incident light is reflected back to its origin thus reflecting the image of the star faces to the spectator. The reflected image of the star is clearly discernable from other reflections created by the surrounding facets. The visibility of the star is however connected with a loss of brightness, fire and scintillation of the cut gemstone since the discernability of the star is caused by a darker reflection of the star compared to the surrounding facets, thus decreasing the splendour and value of the cut gemstone.

Other known cut gemstones, for example some designs from the Charles Covill Odds Collection, are similar to the cut as disclosed in the preamble but the cut gemstone has a reduced brilliance and the image of the star is not clearly reflected towards the spectator looking into the cut gemstone, the reflection of the star is for example distorted by the many facets comprised in the crown of the cut gemstone, making it impossible to distinguish a reflected star-shaped figure in the many reflections.

SUMMARY OF THE INVENTION

The present invention relates to a mixed cut gemstone, according to the preamble of the first claim.

The present invention seeks to add improvements to the existing gemstones and aims at providing a cut gemstone in which a figure resembling a star is reflected clearly visibly towards the spectator with an enhanced brilliance.

It is a further object of this invention that the star resembling figure reflected back to the spectator is surrounded by stripes in order to create the so-called star and stripes effect.

This is achieved according to the present invention with a cut gemstone showing the technical features of the characterising portion of the first claim.

Thereto, each constituent face comprises a third cutting edge extending from the top towards the girdle, a fourth and a fifth cutting edge extending from the first and second star point towards the third cutting edge, the third, fourth and fifth cutting edge converging into a single first intersection point, the first and the fourth cutting edges defining within the constituent face a first star delimiting facet along a first side of the third cutting edge, the second and fifth cutting edge defining with the constituent face a second star delimiting facet along a second side of the third cutting edge opposite the first star delimiting facet, the fourth and fifth cuffing edges defining circumferential facets on a first side of a first striping cutting edge, the first striping cutting edges extending between adjacent first and second star points, a striping facet extending along a second side of the first striping cutting edge opposite the circumferential facet, the striping facets comprising a second striping cutting edge extending from a first star point towards the girdle and a third striping cutting edge extending from a second star point towards the girdle, thus forming concatenated striping facets over the circumference of the pavilion.

The inventors have found that in providing the pavilion with star delimiting facets a clearly visible figure is reflected by the stone, which resembles a star. The star delimiting facets help the spectator to discern the star resembling figure from other reflections and thus add to the visibility of the reflection of the star-shaped figure. The star delimiting facets also increase the amount of light reflected back towards the spectator thus adding to the brilliance of the cut gemstone according to the invention. Next to adding splendour to the cut gemstone, the added brilliance also increases the value of the cut gemstone according to the invention.

The inventors have further found that in adding facets to the pavilion having first striping cutting edges which interconnect pairs of adjacent star points, the star-shaped figure is reflected surrounded by stripes, thus creating an effect of star and stripes for the spectator. The facets added this way further increase the light reflected back to the spectator and thus increase the brilliance of the cut gemstone and thus further add to the splendour and value of the cut gemstone.

Moreover, the inventors have found that the second and third striping cutting edges, reflected through the cut gemstone, create additional stripes which surround the reflected star-shaped figure. In that way an improved delimitation of the star resembling figure from the other reflections in the cut gemstone is obtained and the overall splendour and value of the cut gemstone is improved.

The inventors have further surprisingly found that secondary reflections of the first, second and third striping cutting edges, of the star faces and of the star delimiting facets surprisingly occur in the cut gemstone thus even more increasing the splendour and value of the cut gemstone. The secondary reflections also delimit the reflected star-shaped figure more clearly and allow the star-shaped figure to clearly stand out.

The inventors have moreover surprisingly found that the number and effect of the secondary reflections of the first, second and third striping cutting edges, of the star faces and of the star delimiting facets is increased by adding the striping facets and the circumferential facets to the pavilion thus adding to the overall splendour and value of the cut gemstone.

The image of the star-shaped figure together with the total of the stripes surrounding the star-shaped figure account for the so called star and stripes effect.

In a preferred embodiment of this invention the cut gemstone is characterised in that the first star delimiting facet comprises at least one first emphasizing cutting edge which extends from the first star point and in that second star delimiting facet comprises at least one second emphasizing cutting edge which extends from the second star point, the first and second emphasizing cutting edges converging to each other and intersecting with the third cutting edge at a second intersection point. Due to the presence of the emphasizing edges, visibility of the reflected star-shaped figure is further increased which allows the star to stand out in the total of the reflections of the cut gemstone. The emphasizing cutting edges also further increase the brightness, contrast, fire and scintillation of the cut gemstone.

In further preferred embodiments of this invention the cut gemstone according to the invention is characterised in that the first striping edges form a regular polygon, the constituent faces are congruent, the star delimiting facets are congruent, the star faces are congruent, the striping facets are congruent, the second and third striping cutting edges are of equal length, the pavilion comprises an axis of symmetry having a symmetry number and the axis of symmetry comprises the culet, the symmetry number equals the number of star points, the crown has an axis of symmetry corresponding to the axis of symmetry of the pavilion and finally in that the table is a regular polygon delimited by a number of table cutting edges equal to the symmetry number, the cutting edges of the polygon intersecting in respective corners of the polygon. Next to improving the visibility of the reflected star-shaped figure and stripes, the high degree of symmetry of the thus cut gemstone allows incident rays to be readily and uniformly reflected towards the table, thus adding to the brilliance of the cut gemstone. The high degree of symmetry for a great deal contributes to increasing the value of the cut of the cut gemstone and thus the symmetry to great extend adds to the total value of the cut gemstone.

The high degree of symmetry allows incident light to be reflected in a principle direction which corresponds to the looking direction of a spectator, thus adding to the brightness, contrast, fire and scintillation and thus to the splendour of the cut gemstone as a whole.

The reflection of the striping cutting edges, star faces and star delimiting facets by incident rays of light is also improved due to the higher degree of symmetry, thus adding to the visibility of the star-shaped figure and the striping effect by reflecting the star-shaped figure and the striping cutting edge directly to the spectator or by causing secondary reflections.

Other details and advantages of the cut gemstone according to the invention will become apparent from the enclosed figures and description of preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a preferred embodiment of the crown of a cut gemstone according to the invention.

FIG. 2 shows a preferred embodiment of the pavilion of a cut gemstone according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiment of the cut gemstone (1) shown in FIGS. 1 and 2 comprises a girdle (3), a crown (2) above the girdle (3) and a pavilion (4) below the girdle (3).

The pavilion (4) comprises pavilion faces (32) cut under different angles with the girdle (3) and a culet (6). The pavilion faces (32) comprise star faces (23) and constituent faces (21, 22).

The star faces (23) and the constituent faces (21, 22) alternate in circumferential direction over the pavilion (4). Each constituent face (21, 22) comprises at least a first (11) and second (12) cutting edge. Each star face (23) is delimited from adjacent constituent faces (21, 22) by respectively the first (11) and second (12) cutting edge of the respective adjacent faces (21, 22). Every first cutting edge (11) of a first constituent face (21) intersects with a second cutting edge (12) of a second consecutive constituent face (22) in a star point (9). Every second cutting edge (12) of a first constituent face (21) intersects with a first cutting edge (11) of a second consecutive constituent face (22) in a star point (10).

The first (11) and second (12) cutting edges of consecutive constituent faces (21, 22) intersect in a star point (9, 10) and converge towards the culet (6) so that first (11) and second (12) cutting edges of single first constituent faces intersect in a top (28), pointing towards the culet (6) of the constituent face (21).

The first (11) and second (12) cutting edges can have any length deemed appropriate by the person skilled in the art, however first (11) and second (12) cutting edges of a single constituent face (21, 22) preferably have the same length.

The alternating arrangement of the constituent faces (21, 22) and the star faces (23) and the aforementioned positioning of the constituent faces (21, 22) cause that the constituent faces (21, 22) define a star-shaped figure (33) between them. The star-shaped figure (33) comprises the star faces (23) and the culet (6).

The star faces (23) can have any shape deemed appropriate to the person skilled in the art but preferably are four-sided polygons, more preferably kites. Preferably, every kite is delimited by a first (11) and second (12) cutting edge of consecutive constituent faces (21, 22) and two cutting edges each one extending from the culet (6) towards the top (28) of the consecutive constituent face (21, 22). The dimensions of the individual star faces (23) are not critical to the invention but preferably all star faces are congruent.

The constituent faces (21, 22) comprise a third cutting edge (13) which extends from the top (28) towards the girdle (3) and fourth (14) and fifth (15) cutting edges which extend from the first (9) and second (10) star point respectively and extending towards the third cutting edge (13). The third (13), the fourth (14) and the fifth (15) cutting edges converge into a single first intersection point (29).

The fourth cutting edge (14) can have any length deemed appropriate by the person skilled in the art but preferably is smaller than the length of the first cutting edge (11). The fifth cutting edge (15) can have any length deemed appropriate by the person skilled in the art but preferably is smaller than the length of the second cutting edge (12). More preferably the fourth (14) and the fifth (15) cutting edges have an equal length.

The length of the first (11), second (12), third (13), fourth (14) and fifth (15) cutting edges determine the visibility and shape of the star-shaped figure (33) reflected by the cut gemstone (1), is further also determining for the brightness, contrast, fire and scintillation of the cut gemstone (1) as a whole and is dependent on the material used for the cut gemstone (1) and the size of the original uncut gemstone but can be determined by the person skilled in the art.

The first (11), the third (13) and the fourth (14) cutting edges of first constituent faces (21) define a first star delimiting facet (24). The second (12), the third (13) and the fifth (15) cutting edges of first constituent faces (21) define a second star delimiting facet (25). The first (24) and second (25) star delimiting facets can have any shape deemed appropriate to the person skilled in the art but preferably are triangular, more preferably they are all congruent.

The first constituent faces (21) further comprise first striping cutting edges (18) along the circumference of the pavilion (4) extending between adjacent first and second star points (9, 10). Preferably the first striping cutting edges (18) connect adjacent star points (9, 10). Fourth (14) and fifth (15) cutting edges and first striping cutting edges (18) define circumferential facets (26). The shape of the circumferential facets (26) is not critical to the invention but preferably is triangular.

A second striping cutting edge (19) extends from the first star points (9) towards the girdle (3) and a third striping cutting edge (20) extends from the second star points (10) towards the girdle (3) and the second striping cutting edge (19). The second (19) and third (20) striping cutting edges intersect and define together with the first striping cuffing edges (18) striping facets (27). The striping facets (27) can have any shape deemed appropriate to the person skilled in the art but preferably is triangular.

The length of the second (19) and third (20) striping cutting edges is not critical to the invention but can be determined by the person skilled in the art. Preferably the second (19) and third (20) striping cutting edges intersect near the edge of the girdle (3) of the cut gemstone (1) but this is not critical to the invention. The length of the second (19) and third (20) striping cutting edge is not critical to the invention but preferably the length of the second (19) and third (20) striping cutting edge is equal in each striping facet (27). More preferably, the first striping cutting edges (18) form a polygon and the second (19) and third (20) striping cutting edges intersect on the edge of the girdle (3). Even more preferably, the different striping facets (27) are congruent.

The star delimiting facets (24, 25) preferably comprise additional emphasizing cutting edges (16, 36, 17, 37), spread arbitrarily over the star delimiting facets (24, 25). The emphasizing cutting edges (16, 36, 17, 37) add to the splendour of the cut gemstone (1) by increasing visibility of the reflection of the star-shaped figure (33) so that the star-shaped figure (33) stands out in the total of the reflections of the cut gemstone (1) and add to the brightness, contrast, brilliance, fire and scintillation of the cut gemstone (1).

The position of the emphasizing cutting edges (16, 36, 17, 37) can be determined by the person skilled in the art, but preferably the emphasizing cutting edges (16, 36, 17, 37) extend from first (9) and/or second star points (10) from a first constituent face (21) and intersect with the third cutting edge (13) of the first constituent face (21). The emphasizing cutting edges (16, 36, 17, 37) can have any shape deemed appropriate for the person skilled in the art but preferably are straight. Each star delimiting facet (24, 25) can have any number of emphasizing cutting edges (16, 36, 17, 37) but preferably the first star delimiting facet (24) comprises first emphasizing cutting edges (16, 36) extending from the first star point (9) positioned between the circumferential facet (26) and a star face (23) adjacent to the first cutting edge (11) and the second star delimiting facet (25) comprises second emphasizing cutting edges (17, 37) extending from the second star point (10) positioned between the circumferential facet (26) and a star face adjacent to the second cutting edge (12) extending from the second star point 10. More preferably the first (24) and second (25) star delimiting facets comprise two first emphasizing cutting edges (16, 36) and two second emphasizing cutting edges (17, 37) respectively. First emphasizing cutting edges (16) and second emphasizing cutting edges (17) preferably converge with the third cutting edge (13) of the constituent face (21) in a single second intersection point (30).

The first and second emphasizing cutting edges (16, 17, 36, 37) can have any length deemed appropriate by the person skilled in the art but preferably first emphasizing cutting edges (16, 36) and second emphasizing cutting edges (17, 37) have the same length. More preferably the constituent faces (21) are congruent. Thus a symmetrical star-shaped figure (33) is created since preferably the star faces (23) and the star delimiting facets (24, 25) are congruent and the first (16, 36) and respective second emphasizing cutting edges (17, 37) are equal.

Additional facets (38) can be cut along the striping facets (27), between the girdle (3) and the striping facets (27). In a preferred embodiment of the invention an additional cutting edge extends from every star point (9, 10) towards the girdle (3) thus creating additional facets delimited by the aforementioned cutting edge extending from the star points (9, 10), a cutting edge of the girdle (3) and the second or third striping cutting edge (19, 20). These additionally cut facets along the striping facets (27) can have any shape deemed appropriate by the person skilled in the art but preferably are triangular and more preferably are congruent.

A primary image of the star faces (23) surrounded by adjacent star delimiting facets (24, 25) is reflected directly towards the spectator in the form of a star, wherein the centre of the star coincides with the culet (6). Moreover, secondary images of the star faces (23) surrounded by adjacent star delimiting facets (24, 25) are reflected to the spectator. In case the star-shaped figure (33) comprises an uneven number of star points (9, 10) the secondary images of the star faces (23) surrounded by adjacent star delimiting facets (24, 25) are reflected to the spectator at a position between consecutive legs of the star. Thus created secondary reflections extend from the centre of the table (5) towards the girdle (3) in the spaces left by the primary image. The secondary images are created by secondary reflections of the primary image of the star faces (23) and the star delimiting facets (24, 25) reflected by circumferential (26) and striping (27) facets on an opposed side of the star faces (23) and star delimiting (24, 25) facets of the cut gemstone (1).

Additionally, primary images of cutting edges (18, 19, 20) surrounding the star-shaped figure (33) are reflected directly towards a spectator, next to secondary images of the surrounding cutting edges (18, 19, 20) reflected by facets on an opposite side of the cut gemstone (1). The secondary images of the surrounding cutting edges take the form of circumferential stripes which surround the star-shaped figure (33).

The primary and secondary images of the star faces (23), the star delimiting facets (24, 25) and the cutting edges (18, 19, 20) add to the overall splendour of the cut gemstone (1) and thus substantially contribute to its total value.

The relative shape, angle with the girdle (3) and size of the star faces (23), the star delimiting facets (24, 25), the circumferential facets (26) and the striping facets (27) are determining for the brightness, contrast, fire and scintillation of the cut gemstone (1) as a whole and are dependent on the material used for the cut gemstone (1) and the size of the original uncut gemstone. Furthermore, the shape, size and angle with the girdle (3) of the circumferential facets (26) and the striping facets (27) are determining for reflecting light towards the spectator and thus for the extend to which the secondary image of the star-shaped figure (33) and the secondary image of the surrounding cutting edges (18, 19, 20) is reflected towards a spectator. These determining factors can be determined by the person skilled in the art.

The culet (6) preferably comprises a first axis of symmetry having a first symmetry number. In a more preferred embodiment the first symmetry number equals the number of star points (9, 10). The first symmetry number can be three, four, five, six, seven, eight or more but preferably is uneven due to the possibility of secondary images of the star faces (23) surrounded by adjacent star delimiting facets (24, 25) reflected to the spectator at a left open position between consecutive legs of the star. The number of additional facets (38) along the striping facets (27) preferably is twice the first symmetry number. In case the symmetry number is five the reflected images of the star-shaped figure (33) symbolize the characterising element of the United States Flag, the Stars and Stripes.

Preferably the pavilion (4) comprises a first axis of symmetry of which the first symmetry number is five, the number of star points equals the first symmetry number and the number of additional facets adjacent to the striping facets (27) is ten. When looking directly to the culet, the first striping cutting edges (18) form a first pavilion pentagon delimiting the constituent faces (21, 22). The second (19) and third (20) striping cutting edges form a second pavilion pentagon circumscribing the first pentagon. Finally a pavilion decagon circumscribing the second pentagon is formed by cutting edges of the girdle (3).

Since the different striping facets (27) preferably are congruent, the different first and second striping cutting edges (19, 20) have the same length. The corner points of the first pavilion pentagon therefore are located in the middle of each of the sides of the second pavilion pentagon. The pavilion decagon circumscribes the second pavilion pentagon in such a way that every other corner point of the pavilion decagon coincides with the corner points of the second pavilion pentagon.

The crown (2) comprises a table (5) and a number of other crown facets (31). The crown facets (31) can comprise any number of additional facets deemed appropriate by the person skilled in the art.

The table (5) comprises a number of table cutting edges (34) intersecting in table corners (35). The table (5) can be of any shape deemed appropriate by the person skilled in the art but preferably is large enough so that a spectator can clearly see the reflected primary images of the star faces (23), the star delimiting facets (24, 25) and preferably surrounding cutting edges (18, 19, 20). More preferably the table (5) also allows that secondary reflections of the star faces (23) and the star delimiting facets (24, 25) and/or secondary reflections of the surrounding cutting edges (18, 19, 20) are clearly visible for a spectator.

The shape, angle with the girdle (3) and number of the additional crown facets (31) surrounding the table (5) can be determined by the person skilled in the art and are not critical to the invention. The shape, angle with the girdle (3) and number of the additional crown facets (31) are determining for the brightness, contrast, fire and scintillation of the cut gemstone (1) as a whole and are dependent on the material used for the cut gemstone (1) and the size of the original uncut gemstone.

Preferably first additional crown facets (45) extend from the cutting edges (34) of the table (5) and extend towards the girdle (3). Preferably these first additional crown facets (45) are delimited by a cutting edge (34) of the table (5) and two first additional crown cutting edges (39, 40). The first additional crown facets (45) can be of any shape deemed appropriate by the person skilled in the art but preferably are triangular.

Preferably a second additional crown facet (46) extends from every first additional cutting edge (39, 40) of the first additional crown facets (45) and extends towards the girdle (3). Preferably these second additional crown facets (46) are delimited by a first additional cutting edge (39, 40) of a first additional crown facet (45) and two second additional cutting edges (41, 42). The second additional crown facets (46) can be of any shape deemed appropriate by the person skilled in the art but preferably are triangular.

Preferably third additional crown facets (47) extend from the second additional cutting edges (41, 42) of the second additional crown facets (46) and extend towards the girdle (3). Preferably these third additional crown facets (47) are delimited by a second additional cutting edge (41, 42) of a second additional crown facet (46), a cutting edge of the girdle (3) and a third additional cutting edge (43). The third additional crown facets (47) can be of any shape deemed appropriate by the person skilled in the art but preferably are triangular.

The relative shape, angle with the girdle (3) and size of the first, second and third additional crown facets (45, 46, 47) can be determined by the person skilled in the art and is not critical to the invention.

Preferably, second additional crown facets (46) comprise a subdividing cutting edge 44 which extends from the corner points of the table (5) towards the intersection points of the second additional cutting edges (41, 42).

Preferably, additional first crown facets (45) are congruent, second additional crown facets (46) are congruent and/or third additional crown facets (47) are congruent. Even more preferably the table (5) is a regular polygon. Preferably the table (5) comprises a second axis of symmetry (7). The second axis of symmetry (7) goes through an intersection point (8) with the table, has a second symmetry number and preferably also is an axis of symmetry of the whole crown (2). More preferably, the number of table cutting edges (34) equals the second symmetry number.

Preferably, the second axis of symmetry (7) is collinear with the first axis of symmetry. More preferably the first symmetry number equals the second symmetry number. The second symmetry number can be three, four, five, seven, eight or more but preferably is five.

More preferably, when looking down straight onto the table (5) the first additional cutting edges (39, 40) of the first additional facets (45) form a first crown polygon circumscribing the table (5), the first crown polygon comprising first polygon corner points and first polygon sides. More preferably, the second additional facets (46) form a second crown polygon circumscribing the first crown polygon, the second crown polygon comprising second polygon corner points. Preferably, the second crown polygon corner points are positioned on a cutting edge of the girdle (3). The cutting edges of the girdle (3) preferably form a third crown polygon circumscribing the second crown polygon. Preferably, the table (5) and the first and second crown polygons are regular pentagons and the third crown polygon is a regular decagon.

More preferably, the corner points (35) of the table (5) are located in the middle of the sides of the first crown polygon and the third crown polygon circumscribes the second crown polygon in such a way that every other corner point of the third crown polygon coincides with a corner point of the second crown polygon.

The star points (9, 10) of the star-shaped figure (33) can be positioned deemed appropriate by the person skilled in the art but preferably, for a spectator looking down into the table, on an imaginary line connecting the intersection point (8) of the axis of symmetry (7) with the corner points of the first crown polygon, which preferably is a pentagon. The star-shaped figure is however more preferably positioned with its star points (9, 10) positioned on an imaginary line connecting the intersection point (8) of the axis of symmetry (7) with the corner points (35) of the table (5).

The shape and size of the star-shaped figure (33) in relation to the shape and size of the table (5) can be determined by the person skilled in the art but preferably the length of the side of the first crown polygon equals the length of the sides of the first pavilion pentagon

The different relative shapes, sizes and angles in relation to the girdle (3) of the different cutting edges, faces and facets can be determined by the person skilled in the art in function of the desired brightness, contrast, fire and scintillation of the cut gemstone and are also dependent on the material, size and characteristics of the cut gemstone.

The striping facets (27) are usually positioned under an angle of 50 to 55° with respect to the table (5), the second additional crown facets (46) are usually positioned under an angle of between 30° and 36° with respect to the table (5). If the angle becomes larger than 55°, the height of the stone will increase which goes at the expense of the reflection of the star through the table (5). The star faces (23) are usually positioned under an angle of between 37.5° and 41.5° with respect to the table (5). The striping facets (27) have a height which is (20) to 40% of the height of the pavilion (4). The height of the star-shaped figure is preferably 80-60% of the height of the pavilion (4). If the angle becomes less than 30° the dimensions of the table (5) would decrease to such an extent that the star would no longer be visible through the table (5).