CUTTING METHOD FOR A DIAMOND WITH LOW DEPTH PERCENTAGE AND RESULTANT CUT DIAMOND

Abstract

A gemstone, and a method for cutting a gemstone, such that the resulting gemstone has a total depth percentage of between 38-55% but still provides for a brilliant cut without having face main facets intersect a cullet.

Claims

1. A cut gemstone including: a crown and a pavilion separated by a girdle, each of said crown and said pavilion being cut to have multiple facets, said pavilion facets including: a cullet facet; belly main facet contacting said girdle facet and said cullet facet; a face main facet contacting said girdle facet but not said cullet facet; a shoulder main facet between said belly main facet and said face main facet; at least two pavilion half facets between said belly main facet and said shoulder main facet; and at least two pavilion half facets between said shoulder main facet and lace main facet; wherein said belly main facet has a facet angle between 28 and 38 degrees; wherein said face main facet has a facet angle between 28 and 38 degrees; and wherein a total depth of said gemstone is between 35 percent and 55 percent of a dimeter of said girdle.

2. The cut gemstone of claim 1 wherein said cut gemstone is a cut diamond.

3. The cut gemstone of claim 1 wherein said gemstone girdle is generally an oval.

4. The cut gemstone of claim 1 wherein said gemstone girdle is generally a marquise.

5. The cut gemstone of claim 1 wherein said gemstone girdle is generally a pear.

6. The cut gemstone of claim 1 wherein said gemstone girdle is generally a cushion.

7. The cut gemstone of claim 1 wherein: said crown has a crown angle; said pavilion has a pavilion angle; and said crown angle is greater than said pavilion angle by between 6 degrees and 12 degrees inclusive.

8. The cut gemstone of claim 1 wherein a twist angle of said pavilion is between 30 and 40 degrees.

9. The cut gemstone of claim 1 wherein said shoulder main facet has a facet angle of between 25 and 33 degrees.

10. The cut gemstone of claim 1 wherein said facet angle of said shoulder main facet is less than said facet angle of said ace main facet.

11. The cut gemstone of claim 1 wherein said cullet is in the shape of an elongated hexagon.

12. The cut gemstone of claim 1: wherein, said shoulder main facet and said belly main facet meet at a first portion of a line of intersection; wherein, said at least two pavilion half facets between said shoulder main facet and said belly main facet meet at a second portion of said line of intersection; and wherein, said first portion of said line of intersection is equal to or longer than said second portion of said line of intersection.

13. The cut gemstone of claim 1 wherein said crown includes a kite facet, at least two crown half facets, a table, and a star facet.

14. The cut gemstone of claim 13 wherein an average table diameter is between 54 and 64 percent of an average diameter of said girdle.

15. The cut gemstone of claim 13 wherein said cut gemstone includes 58 total facets.

16. The cut gemstone of claim 1 wherein said shoulder main facet contacts said girdle facet and said cullet facet.

17. The cut gemstone of claim 1 wherein said cullet has an average diameter of less than 5 percent the average diameter of the girdle.

18. A cut gemstone including: a crown and a pavilion separated by a girdle, each of said crown and said pavilion being cut to have multiple facets, said pavilion facets including: a cullet facet; a belly main facet contacting said girdle facet but not said cullet facet; a face main facet contacting said girdle facet but not said cullet facet; a shoulder main facet between said belly main facet and said face main tweet; at least two pavilion half facets between said belly main facet and said shoulder main facet; and at least two pavilion half facets between said shoulder main facet and face main facet; wherein said belly main facet has a facet angle between 28 and 36 degrees; wherein said face main facet has a facet angle between 30 and 36 degrees; and wherein a total depth of said gemstone is between 35 percent and 55 percent of a diameter of said girdle.

19. The cut gemstone of claim 18: wherein, said shoulder main facet and said belly main facet meet at a first portion of a line of intersection; wherein, said at least two pavilion half facets between said shoulder main facet and said belly main facet meet at a second portion of said line of intersection; and wherein, said first portion of said line of intersection is equal to or longer than said second portion of said line of intersection.

20. The cut gemstone of claim 18 wherein a twist angle of said pavilion is between 30 and 40 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 depicts a side view of an embodiment of a flat (depth percentage less than or equal to 55%) diamond with a pavilion cut in accordance with the present disclosure

[0033] FIG. 2 provides a top (crown) view of the cut oval diamond of FIG. 1.

[0034] FIG. 3 provides a bottom (pavilion) the cut oval diamond of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0035] The following detailed description and disclosure illustrates by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the disclosed systems and methods, and describes several embodiments, adaptations, variations, alternatives and uses of the disclosed systems and methods. As various changes could be made in the above constructions without departing from the scope of the disclosures, it is intended that all matter contained in the description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

[0036] The present disclosure is directed to a method for shaping a gemstone such that the resulting stone has a total depth percentage of less than 55%. Ideally, the depth percentage is less than 50% and will commonly be from around 38% to around 45% making the diamond traditionally fall into a category of being very flat. As described herein, this method and resulting cut shape, is suitable for use with any technique for shaping any gemstone, but is believed particularly useful for diamonds. This method may be used for any shape of cut gemstone, but is particularly useful for fancy shapes including, but not limited to, cushion, marquise, oval, round, and pear cuts. This disclosure will discuss specifically how to apply sizing and facet arrangement to oval shapes, but one of ordinary skill will understand how to adapt the teaching herein to other cuts as the principles remain the same across different shapes.

[0037] In general, the present method of cutting, and the resultant cut gemstone, provide for improved light handling through the use of steeper angles applied to the pavilion main facets than would traditionally be done with a stone of the indicated depth percentage. This is commonly performed through the inclusion of a cullet (119) which will typically be hexagonal, octagonal, or parallelogram in shape and which will generally only intersect some of the pavilion main facets (301), (303), and (305). Specifically, the pavilion face main facets (301) (at the elongated portions of the stone) will generally not intersect with the cullet (119). The inclusion of a cullet (119) importantly allows for the pavilion main facets (301), (303), and (305) to go to a greater while still providing a base to the stone. It particularly allows for the pavilion face main facets (301), and the pavilion belly main facets (303) to have steeper angles than they would in a traditional brilliant cut (which would result in a shallow cut with a stone of this total depth percentage).

[0038] FIG. 1 provides a side view of an embodiment of a low depth brilliantly cut flat oval diamond with an 8 main configuration in the pavilion cut in accordance with the present disclosure. FIG. 2 provides a top view of the cut oval diamond of FIG. 1. FIG. 3 provides a bottom view of the cut oval diamond of FIG. 1. The drawings will generally all be discussed interchangeably. The diamond shown in the drawings provides for the traditional 58 facet positioning for a modified brilliant cut oval diamond (with a cullet) and, for ease of discussion, the various facets are labeled so they may be referred to herein specifically. The crown (103) includes the table (109), crown main or kite facets (201), (203), and (205), crown star facets (215), and crown half facets (207) and (209). The pavilion (105) includes the pavilion main facets (301), (303) and (305), pavilion half facets (207) and (209) and the cullet (119). A girdle (107) separates the crown (103) and pavilion (105). It should be recognized that the numbering system is such that the facets in the crown (103) aligned with a facet in the pavilion (105) generally share the same last two digits but the facets in the crown begin with 2 while those in the pavilion begin with 3.

[0039] While the above provides the basic facets, it should be recognized that both the main facets and half facets each utilize two different numbers. This is to reference the specific location of the facets as this diamond is not round and thus facet positioning relative to the shape of the stone is important. Specifically, the main facets at the elongated ends of the stone (head and tail) are referred to as crown face main facets (201) and pavilion face main facets (301). The main facets positioned at the constricted ends are referred to as the crown belly main facets (203) and pavilion belly main facets (303). Finally, the main facets located between face and belly mains (essentially around the curve) will be referred to as the crown shoulder main facets (205) and pavilion shoulder main facets (305). With regards to the half facets, a thee half facet (209) or (309) is positioned between a shoulder half facet (207) or (307) and a face main facet (201) or (301) or belly main facet (203) and (303) while a shoulder half facet (207) or (207) is positioned between a face half facet (209) or (309) and a shoulder main facet (203) or (303).

[0040] It should be recognized that FIGS. 1 through 3 provide for an oval cut, the positioning and labeling of facets would apply to other limey cuts as other fancy cuts in the modified brilliant form are generally just modifications of the oval. For example, a marquise (lens) shape would simply have the face main facets (201) and (301) produce a point, a pear shape would have one end like a marquise and the other like an oval, and a cushion could be considered similar to an oval without as much elongation along one axis.

[0041] In older to provide for improved appearance in a stone with decreased depth percentage, it should first be recognized what is meant by decreased depth percentage. Regardless of shape, the total depth percentage of diamonds cut in accordance with this disclosure will generally be less than 55%, preferably less than 52%, preferably less than 50%, preferably less than 45%, and more preferably between 38% and 45%.

[0042] Within the above range, generally a substantially increased amount of the total depth will also be in the crown as opposed to the pavilion. In many respects, the present embodiments will provide for a crown which is only slightly shallower than a standard modified brilliant corresponding to the shape and may be over the same relative depth. Instead of discussing this herein in conjunction with depth percentage, it is actually more logical to discuss it in terms of pavilion and crown angles. It is generally preferred that the crown angle (509) and the pavilion angle (519) be different by about 5 to about 12 degrees with a difference of around 6 to around 8 degrees being preferred. It is also generally be preferred that the crown angle (509) be about 28 degrees to about 38 degrees (alternatively between 30 and 36 degrees). The pavilion angle (519) will also typically be around 28 to around 38 degrees (alternatively between 30 and 36 degrees). The reason for the similar range is that typically a lower pavilion angle will be used with a higher crown angle and vice-versa. It is generally preferred, however, that the crown angle (509) be greater than the pavilion angle (519) which is backward to a more traditional brilliant cut. It should be recognized that the proposed angles are subject to some variation and interplay based on total available depth as stones on the deeper end of the total depth percentage spectrum are likely to have different arrangements than stones on the shallower end and the natural variations within stone formation mays encourage particular selections. The table (109) will generally also be of traditional desired size having an average diameter of around 54 percent to around 63 percent of the average diameter of the girdle (107).

[0043] As should be apparent from the above, by maintaining a generally similar crown angle (509) to traditional cuts, the crown facets will generally be broadly similar to the cutting of standard modified brilliant cuts and will commonly be within ranges perceived as high quality for standard modified brilliant cuts. In the present embodiment, most of the change in the cut is actually made to the pavilion (105) of the diamond. In this way, the diamond, when viewed from the table (109), will look quite similar to a standard modified brilliant cut based on positioning of facets the crown (103) while haying better light direction from the pavilion (105).

[0044] The pavilion (103) of an exemplary stone from an embodiment is shown best in FIG. 3. In the embodiment of FIG. 3, the main facets are arranged so as to have steeper angles than would be traditional on a stone this flat. This is generally done through modification of the points of interaction between facets and the twist imparted to the facets which can alter their side to side width. Speaking broadly, changes made to the stone are to tilt out the main facets (301), (303), and (305). This is performed generally by including a cullet (119) which serves to allow the bottom ends of the pavilion main facets (201), (203), and (205) to be spaced further from each other. A second change is to not have all the pavilion main facets (201), (203), and (205) reach the cullet at all. This provides for the bottom ends of the main facets to be further pushed from each other. For fancy cuts (which are often non-symmetric) generally the pavilion face main facets (301), which are at the elongated ends, are moved from contacting the cullet (119) first, followed by the pavilion belly main facets (303). The pavilion shoulder facets (305) will generally contact the cullet (119) in virtually all arrangements. While this pattern is preferred, for certain cuts it may be desirable to move the pavilion main facets (301), (303), and (305) away from the cullet in a different pattern. It should be recognized that the shape of the cullet (119) which would traditionally be octagonal, is commonly reduced to an elongated hexagon or parallelogram as various main facets cease contacting it.

[0045] In the embodiment of FIG. 3, the cullet facet (119) is preferably present and will gene rally have an average diameter of around 0.01% to around 6% of the average diameter of the girdle (107) with a preference being toward the larger end of around 4% to around 6%. It is, therefore, substantially smaller than many older cut diamonds which utilized a large cullet, but larger than many modern diamonds where they are used sparingly if at all (often to preserve weight). As indicated above, the presence of a cullet (109) pushes the main facets to a steeper angle as the main facets do not need to actually reach a point but simply need to reach the cullet (119).

[0046] In the embodiment of FIG. 3, the pavilion face main facets (301) do not reach the cullet (119) but the pavilion belly main facets (303) do. This will be a common arrangement to provide for similar angle between the pavilion belly main facets (303) an the pavilion face main facets (301) as discussed later since the pavilion belly main facets (303) have less distance to travel and can more readily be made at steeper angles. As can be seen in FIG. 3, terminating, the pavilion face main facets (301) shy of the cullet (119) creates a line of intersection (351) between the two pavilion shoulder main facets (305) on either side of the pavilion face main facets (301). It should be apparent that having this premature termination results in the pavilion face main facets (301) having a steeper angle than they would if they extended to the cullet (119). The diamond therefore gains artificial depth. Depending on the specific embodiment, the pavilion face main facets (301) will preferably have an angle of around 30 degrees to around 36 degrees.

[0047] The belly main facets (303) will generally reach to the cullet and will commonly be arranged to have a similar angle to the face main &cos (301). Specifically, the belly main facets (303) will generally have an angle of around 28 to around 36 degrees. The belly main facets have a greater window of variation because in most fancy cuts the stone is not round. As discussed above, this type of cut is particularly useful in fancy shaped diamonds. In such diamonds, one dimension is always elongated compared to the other. Because of that, the pavilion face main facets (301) and pavilion belly main facets (303) will have different distances to travel to reach the cullet (119) if they are at the same angle. Specifically, as can be seen in FIG. 3, the pavilion belly main facets (303) generally have to travel less distance to reach the cullet (119) than the pavilion face main facets (301). Thus, the pavilion belly main facets (303) will often reach the cullet (119) even while the pavilion face main facets (301) do not.

[0048] It should be noted that while the pavilion belly main facets (303) reaching the cullet (119) is generally preferred, it is not required and in some stones, particularly those toward the lower end of the depth percentage ranges presented above, the pavilion belly main facets (303) may also fail to reach the cullet (119). In this particular embodiment where neither the pavilion face main facets (301) or the pavilion belly main facets (303) react the cullet (119), the pavilion shoulder main facets (305) will generally define the cullet (119).

[0049] The pavilion shoulder main facets (305) generally cannot be at as steep of an angle as the pavilion face main facets (301) or pavilion belly main facets (303). Therefore, the pavilion shoulder main facets (305) will generally be at an angle of between about 25 degrees and about 33 degrees. Because the pavilion shoulder main facets (305) essentially always contact the cullet (119) and because the pavilion shoulder main facets (305) generally have less distance to travel to the cullet (119) than the pavilion face main facets (301), the angle of the pavilion shoulder main facets (305) will generally always be less than that of the pavilion face main facets (301).

[0050] While the pavilion main facets (301), (303), and (305) provide for much of the brilliance of a cut gen stone, it should be recognized that with their position adjustment, the pavilion halves (307) and (309) have also been adjusted both to allow the main facets to be positioned as indicated while still making a symmetrical cut and to provide for their illumination effects. Normally, paired pavilion halves would be generally symmetrical about each other, but in the present diamond that is not necessarily the case. Specifically, the pavilion shoulder halves (307) will generally have an angle of about 27 to about 32 degrees while the pavilion face halves (309) will commonly also be around 27 to around 32 degrees but will typically always be at greater angle than the pavilion shoulder halves (307). Much of the arrangement of the halves is simply to present angles which allow for the corners of the stone to be turned between the main Facets (301), (303), and (305) when the main facets (301), (303), and (305) are at the angles contemplated above. For example, as the pavilion shoulder main facets (305) will have less angle than the pavilion thee main facets (301) (and usually the pavilion belly main facets (303) also), the shoulder half facets (307) will typically have less angle than the face half facets (307) to allow for transition between them while keeping all facet faces flat and the stone symmetrical.

[0051] In many respects, the pavilion half facet (307) and (309) angles are chosen to simply get angles between the pavilion main facets (301), (303), and (305) with a facet surfaces using the correct 58 facet arrangement of a modified brilliant. How they are positioned is actually commonly best understood by using the twist (529) of the diamond. Twist (529) is a characteristic of a diamond commonly used by diamond cutters, but which is often not used in the retail sale of jewelry. Twist (529) is the angle between adjacent main facets. Generally, the twist (529) for the pavilion (105) and the twist (529) for the crown (103) will be the same as the facets are concentrically arranged between the two, thus while the twist (529) shown in FIG. 2, it would apply equally to FIG. 3.

[0052] In the present oval diamond, a twist of between about 30 degrees and about 40 degrees is preferred. Generally the rounder the diamond, the greater the twist (529), but in the present embodiments, keeping the twist in this range regardless of shape (e.g. also using the same twist range on marquise, pear, and cushion shapes) while simply making the halves (307) and (309) steeper on rounder stones (for example, cushion cuts or rounder ovals) is expected to provide for improved light handling.

[0053] While the above has discussed a great deal of the facet positions and angles, there is also one more element of facet intersection to discuss. As contemplated above, the pavilion face main facets (301) and pavilion belly main facets (303) are generally positioned so as to be at a greater angle than would be expected given the depth of the stone. In many respects, this results in them being pushed out at the cullet (119). Because of this, the line of intersection between the pavilion main facets (301), (303), and (305) and the neighboring half facets (307) and (309) is moved and its angle is altered. This can be seen in FIGS. 1 and 3 and is best understood by comparing the relative lengths of the facet edges (401) and (403). The facet edge (403) is the edge formed between two adjacent pavilion main facets such as the pavilion shoulder main facet (305) and pavilion belly main facet (303) which is element indicated by this reference shown in FIG. 3. The facet edge (401) is the edge between the two half facets (307) and (309) between the same two mains as also indicated. It should be recognized, that while (401) and (403) are indicated to be two different facet edges, they are typically only one edge so they are co-planar in at least one plane and may be co-linear. It should be recognized that mathematical specificity is not required and specific variations in the ability to accurately cut diamonds will typically result in them not being perfectly co-planar or co-linear, however, that is commonly a target arrangement.

[0054] In a typical modified brilliant, the two lengths are such that the length (403) is substantially shorter than the length (401). In the depicted embodiment, however, the length (403) is actually closer to the same length as length (401), may be equal to the length of length (401), or length (403) may even be greater than the length (401). This is generally caused by the pushing out of the main facets as contemplated above to give them a greater angle while still having a stone of decreased depth and enabling the facets to correctly interface with the girdle (107).

[0055] While the above provides for the arrangement of facets for an oval brilliant cut, it would be understood by one of ordinary skill in the art how to adapt the above for other fancy cuts, and even for round cuts. For example, for a marquise cut, each pavilion face main facet (301) would typically not reach the cullet (11) and the pavilion thee halves (209) would be positioned so as to produce a sharper point. A pear shape would incorporate a single pavilion face main facet (301) as shown in FIG. 3 at the base of the pear and a pavilion face main facet (301) at the point in the manner of a marquise as above. A pillow cut will commonly simply have a much more squared shape than the oval which may result in the pavilion belly main facets (303) not reaching the cullet (119) or having slightly different angle.

[0056] Finally, the above principles may be used on a round cut, with any differences between the pavilion belly main facets (303) and the pavilion face main facets (301) generally being eliminated as these would generally be identical facets. It should be recognized that the cut is generally not preferred for a round cut stone as a round cut does not have clearly defined pavilion shoulder main facets (305) as effectively all the main facets are the same. Therefore, having to have each alternating, main facet (which is effectively the positioning of the pavilion shoulder main facets (305) compared to the others) have a reduced angle will produce a stone which is not cut symmetrically around a center axis. As such symmetry is usually preferred for round cuts, the present embodiment may produce a less desirable round cut than it does for others.

[0057] The qualifier generally and similar qualifiers, as used in the present ease, would be understood by one of ordinary skill in the art to accommodate recognizable attempts to conform a device to the qualified term, which may nevertheless tall short of doing so. This is because terms such as planar are purely geometric constructs and no real-world component is a true plane in the geometric sense. Variations from geometric and mathematical descriptions are unavoidable due to, among other things, manufacturing tolerances and individual manufacturing skill resulting in shape variations, detects and imperfections, non-uniform thermal expansion, and natural wear. Moreover, there exists for every object a level of magnification at which geometric and mathematical descriptors fail due to the nature of matter. One of ordinary skill would thus understand the tem generally, and relationships contemplated herein regardless of the inclusion of such qualifiers, to include a range of variations from the literal geometric meaning of the term in view of these and other considerations.

[0058] While the invention has been disclosed in conjunction with a description of certain embodiments, including those that are currently believed to be the preferred embodiments, the detailed description is intended to be illustrative and should not be understood to limit the scope of the present disclosure. As would be understood by one of ordinary skill in the art, embodiments other than those described in detail herein are encompassed by the present invention. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the invention.

[0059] It will further be understood that any of the ranges, values, properties, or characteristics given for any single component of the present disclosure can be used interchangeably with any ranges, values, properties, or characteristics given for any of the other components of the disclosure, where compatible, to form an embodiment having defined values for each of the components, as given herein throughout. Further, ranges provided for a genus or a category can also be applied to species within the genus or members of the category unless otherwise noted.