Shallow Depth Cut Diamonds
The invention is directed to shallow pavilion, cut diamonds having excellent optical characteristics. The pavilion surface includes a plurality of substantially planar main pavilion facets, each of which extend from the girdle to a pointed culet defining the bottom most portion of the cut diamond. The crown angle is in the range of between about 29 degrees to about 36 degrees, and the pavilion angle is in the range of between about 15 degrees and about 34.5 degrees. The shallow pavilion, cut diamonds of the invention may be either round shaped cut diamonds orfancy shaped cut diamonds.
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The invention is directed to finished cut diamonds that have both excellent optical characteristics and exceptionally high yield for the finished stones. More specifically, the present invention provides both round and fancy shallow pavilion cut diamonds with exceptional optical characteristics.
DESCRIPTION OF THE PRIOR ARTIn the United States market, the round, brilliant cut has been the round diamond market standard since it was developed by Marcel F. Tolkowsky in 1919. The round, brilliant cut and most other popular round cut diamonds include a relatively tall crown height, steep pavilion angle, and high total depth percentage. As a result, the girdle diameter of these stones is relatively small in comparison to their pavilion depth and the total depth of the stone. While prior art round, brilliant cut diamonds have excellent optical characteristics, their tall crown height requires a relatively high stone weight for a cut diamond of a given girdle diameter. For some rough diamond stones, this tall crown height can result in a higher than optimal loss of weight during the cutting and polishing process when converting the rough diamonds to finished stones.
Some rough diamonds, having a depth of less than about 3 mm (known in the trade as “flat stones”), are too shallow for cost efficient cutting into round, brilliant cut diamonds. The strong market preference for deep pavilion round, brilliant cut finished diamonds has rendered such flat stones (low overall depth) nearly unmarketable for use in creating high optical quality round, brilliant cut finished diamonds. One of the reasons round, brilliant cut diamonds utilize steep pavilion angles was the belief that deep pavilions were necessary to avoid the optical characteristic known in the trade as the “fish eye effect.” This optical effect occurs when light loss from within one or more of the diamond's internal surfaces are sufficient that the table, when viewed from above, includes one or more areas that are substantially darker than the rest of the diamond. Such darkened “fish eye” areas are considered to be highly undesirable in a cut, finished diamond. traditionally had relatively steep pavilion angles in order to avoid inferior optical characteristics, such as the “fish eye” effect, in the finished fancy diamond. Similar to the case with the prior art round brilliant cut diamonds, the steep pavilion angles and relatively tall crown heights of the prior art fancy cut diamonds resulted in higher than optimal loss of weight (low cut weight yield) during the cutting and polishing processes.
Surprisingly, the applicant has found that cut diamonds with relatively shallow pavilion angle cuts combined with the other parameters set forth below have optical characteristics that are at least equivalent to, and often superior to, the prior art standard fancy cuts and round, brilliant cut diamonds. Moreover, due to their shallow pavilion depth, the cutting and polishing weight loss is significantly reduced for many rough stones. Further, the higher proportion of girdle diameter (round cut) or surface area (fancy cut) to stone weight provides the visual impression to consumers that the stone is significantly larger than its actual carat weight. Moreover, the applicant has discovered that round, cut diamonds with excellent optical characteristics may be cost efficiently cut from “flat stones,” which can further reduce the cost of the round, shallow pavilion cut stones of the invention relative to the round, brilliant cut diamonds of the prior art.
OBJECTS OF THE INVENTIONIt is an object of the invention to provide a shallow pavilion angle round, cut diamond that has good sparkle characteristics.
It is an object of the invention to provide a shallow pavilion angle fancy, cut diamond that has good sparkle characteristics.
Another object of the invention to provide a shallow pavilion cut diamond with enhanced light reflection amplification.
It is another object of the invention to provide a cut diamond with good optical characteristics that appears, when viewed from above, to be larger/heavier than its actual size/weight of the cut stone.
It is a still further object of the invention to provide round, cut diamonds that have significantly higher cut weight yield relative to the prior art round, brilliant cut diamonds.
It is another object of the invention to provide high optical quality round cut, diamonds from so called rough “flat stone” diamonds.
SUMMARY OF THE INVENTIONIn a first preferred embodiment, the invention includes a cut diamond having a round shape. The round cut diamond including a table having a table plane and a substantially annular girdle. The round cut diamond has a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage. A crown surface is located between the table and the substantially annular girdle and extends in a crown angle to the table plane. A pointed culet defines the bottom most portion of the round cut diamond. A pavilion surface extends at a pavilion angle relative to the table. The crown angle is in the range of between about 29 degrees to about 36 degrees, and the pavilion angle is in the range of between about 25 degrees and about 36 degrees.
The invention further includes fancy cut diamonds with a table having a table plane and a girdle having a non-circular circumference. The fancy cut diamonds have a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage. A crown surface is located between the table and the girdle and extends in a crown angle to the table plane. A pavilion surface extends at a pavilion angle relative to the table. The pavilion surface includes a plurality of substantially planar main pavilion facets each of which extend from the girdle having a non-circular circumference to a pointed culet defining the bottom most portion of the cut diamond. The crown angle is in the range of between about 29 degrees to about 36 degrees and the pavilion angle is in the range of between about 15 degrees and about 34.5 degrees. For the purposes of this application, the phrase “fancy cut diamond” includes all cut diamond shapes that are other than substantially round (when viewed from above), shaped diamonds.
In another aspect, the present invention is further directed to cut diamonds having a table with a table plane and a girdle. The cut diamonds have a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage. A crown surface is located between the table and the girdle and extends in a crown angle to the table plane. A pavilion surface extends at a pavilion angle relative to the table. The pavilion surface includes a plurality of substantially planar main pavilion facets, each of which extend from the girdle to a pointed culet defining the bottom most portion of the cut diamond. The crown angle is in the range of between about 29 degrees to about 36 degrees, and the pavilion angle is in the range of between about 15 degrees and about 34.5 degrees. The cut diamonds in accordance with this aspect of the invention may be either round shaped cut diamonds or fancy shaped cut diamonds.
The organization and manner of the structure and function of the invention, together with the further objects and advantages thereof, may be understood by reference to the following description taken in connection with the accompanying drawings, and in which:
In accordance with a first embodiment of the invention,
More specifically, as can be seen in
In marked departure from the prior art round, brilliant cut diamonds, the present inventor has discovered that at least equivalent reflection pattern can be obtained by providing a round, shallow pavilion diamond with a very shallow pavilion, namely by forming the pavilion angles in the range of twenty five to thirty six degrees, preferably thirty to thirty two degrees, as opposed to the conventional pavilion angles which are in the range of 40 to 43 degrees. Put another way, when matched for diamond diameter and viewed from above, the round, shallow pavilion diamonds of the invention provide a stone with the same top down view and at least equivalent optical characteristics to the prior art round, brilliant cut diamonds of significantly higher carat weight. The round, shallow pavilion diamonds have a carat weight that is between 10% and 20% (typically 16%-18%) less than a matched diameter prior art, round brilliant cut diamonds. Furthermore, the shallow pavilion diamonds of the present invention can realize unexpected brilliance and light amplification characteristics with total depth percentage in a range from about twenty five percent to about fifty percent. This contrast with the total depth percentage range of between 55 to 64 percent for prior art round, brilliant cut diamonds. The maximum and minimum crown angles for the shallow pavilion, round diamonds of the invention are between about thirty two degrees and thirty six degrees with the preferred crown angles ranging from thirty three to thirty five degrees.
Table 1 below provides the relevant parameters for the round, shallow pavilion diamonds of the invention, indicating in each instance a minimum value, a maximum value and a preferred range.
In contrast to the prior art, the light pattern for round, shallow pavilion cut diamond 20 of the invention, follows a path whereby light is reflected from one pavilion surface to an opposed crown surface, then another pavilion surface, then to the table, then back to a pavilion surface, then to the crown, then to an opposed pavilion surface and only then out to the table. This light pattern, with light rays being repeatedly reflected and refracted between many diamond surfaces creates an unexpectedly brilliant light display for a shallow pavilion, round cut diamond. As a result of the repeated reflection and refraction, the light transmitted from the table 22 of the shallow pavilion, round diamond 20 during the OGI Systems Ltd. CFire™ optical performance test is an impressive 69% as illustrated in
The crown angle for the prior art round, brilliant cut diamond shown in
In accordance with another aspect of the invention, a variety of shallow pavilion, fancy cut diamonds are provided four embodiments of which are illustrated in
Turning to the cushion shaped, shallow pavilion diamond 120 of the invention shown in
More specifically, as can be seen in
The present inventor has discovered that a brilliant-like reflection pattern can be obtained by providing a cushion shaped, cut diamond and other fancy cut diamond shapes with a shallow pavilion angle combined with a pointed culet at the bottom of the pavilion. The pavilion angles for the fancy cut diamonds of the invention range between twenty five to thirty four and one half degrees, preferably between thirty to thirty two degrees. By utilizing the combination of a pointed culet and shallow pavilion angle in accordance with the fancy cut diamonds of the invention realizes improved brilliance and light amplification characteristics relative to traditional steep pavilion angle fancy cut diamonds of the prior art. The maximum and minimum crown angles for the shallow pavilion, fancy cut diamonds of the invention are between about twenty nine degrees and about thirty four and one half degrees. The crown angle for the shallow pavilion, fancy cut diamonds of the invention are preferably in the range of from thirty and thirty five degrees.
By adhering to the criteria set forth in the Table 2, the light pattern for shallow pavilion, fancy cut diamonds 120, 120B, 220, 220A, 320 and 420 of the invention, follows a path whereby light is reflected from one pavilion surface to an opposed crown surface, then to another pavilion surface, then to the table, then back to a pavilion surface, then to the crown, then to an opposed pavilion surface and only then out to the table in a manner similar to that shown above in
The heart shaped, shallow pavilion diamond 220 of the invention is comprised of a total of 56 facets. The crown 224 has 32 facets including a single table facet 222, eight bezel facets 221, eight star facets 223, and fifteen upper girdle facets 225. The pavilion 226 comprises a total of twenty four facets including sixteen lower girdle facets 227, seven main pavilion facets 229, and a single pointed culet 230 as best seen in
The pear shaped, shallow pavilion diamond 320 of the invention is comprised of a total of 56 facets. The crown 324 has 33 facets including a single table facet 322, eight bezel facets 321, eight star facets 323, and sixteen upper girdle facets 325. The pavilion 326 comprises a total of 23 facets including sixteen lower girdle facets 327, six main pavilion facets 329, and a single pointed culet 330 as best seen in
The oval shaped, shallow pavilion diamond 420 of the invention is comprised of a total of 58 facets. The crown 424 has a total of 33 facets including a single table facet 422, eight bezel facets 421, eight star facets 423, and sixteen upper girdle facets 425. The pavilion 426 comprises a total of twenty-five facets including sixteen lower girdle facets 427, eight main pavilion facets 429, and a single pointed culet 430 as best seen in
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific embodiments disclosed herein, but only by the appended claims.
Claims
1. A cut diamond having a round shape, the cut diamond comprising:
- a table having a table plane and a substantially annular girdle, the cut diamond having a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage;
- a crown surface located between the table and the substantially annular girdle and extending in a crown angle to the table plane;
- a pointed culet defining the bottom most portion of the cut diamond; at least three pavilion surfaces, each extending at a pavilion angle relative to the table plane; and, wherein the crown angle is in the range of 29 degrees to 36 degrees and the pavilion angle is in the range of 25 degrees to 36 degrees.
2. The round cut diamond of claim 1 wherein the total depth percentage is in the range of 25 percent to 50 percent.
3. The round cut diamond of claim 1 wherein the table diameter is in the range of 55 percent to 85 percent.
4. The round cut diamond of claim 1 wherein the crown height is in the range of out 7 percent to 15 percent.
5. The round cut diamond of claim 2 wherein the total depth percentage is in the range of 35 percent to 47 percent.
6. The round cut diamond of claim 3 wherein the table diameter is in the range of 66.5 percent to 85 percent.
7. The round cut diamond of claim 4 wherein the crown height is in the range of 9 percent to 12 percent.
8. The round cut diamond of claim 1 wherein the pavilion angle is in the range of 30 degrees to 33 degrees.
9. A fancy cut diamond comprising:
- a table having a table plane and having a non-circular circumference girdle, the cut diamond having a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage;
- a crown surface located between the table and the girdle having a non-circular circumference and extending in a crown angle to the table plane;
- at least three pavilion surfaces, each extending at a pavilion angle relative to the table, the pavilion surface includes a plurality of substantially planar main pavilion facets, each of the plurality of substantially planar main pavilion facets extend from the girdle having a non-circular circumference to a pointed culet defining the bottom most portion of the cut diamond; and,
- wherein the crown angle is in the range of 29 degrees to 36 degrees and the pavilion angle is in the range of 15 degrees to 34.5 degrees.
10. The fancy cut diamond of claim 9 wherein the pavilion angle is in the range of 22 degrees to 33 degrees.
11. The fancy cut diamond of claim 9 wherein the table diameter is in the range of 60 percent to 85 percent.
12. The fancy cut diamond of claim 9 wherein the diamond has a pear shape.
13. The cut diamond of claim 9 wherein the diamond has a cushion shape.
14. The fancy cut diamond of claim 9 wherein the diamond has a heart shape.
15. A cut diamond comprising:
- a table having a table plane and a girdle, the cut diamond having a shape and configuration that results in a specific total depth percentage, a specific crown height percentage, a specific girdle height percentage and a specific table percentage;
- a crown surface located between the table and the girdle and extending in a crown angle to the table plane;
- at least four pavilion surfaces, each extending at a pavilion angle relative to the table, the pavilion surface includes a plurality of substantially planar main pavilion facets, each of the plurality of substantially planar main pavilion facets extend from the girdle to a pointed culet defining the bottom most portion of the cut diamond; and,
- wherein the crown angle is in the range of 29 degrees to 36 degrees and the pavilion angle is in the range of 15 degrees to 34.5 degrees.
16. The cut diamond of claim 15 wherein the total depth is in the range of 25 percent to 55 percent.
17. The cut diamond of claim 15 wherein the table percentage is in the range of 50 percent to 90 percent.
18. The cut diamond of claim 15 wherein the crown height is in the range of 7 percent to 15 percent.
19. The cut diamond of claim 15 wherein the pavilion angle is in the range of 22 degrees to 33 degrees.
20. The cut diamond of claim 15 wherein the diamond has a round shape.
21. The cut diamond of claim 15 wherein the diamond has an oval shape.
Type: Application
Filed: Sep 30, 2016
Publication Date: Sep 12, 2019
Applicant:
Inventor: Leszek Tomasik (Itasca, IL)
Application Number: 15/283,194