Hearts & Arrows SiC Gemstone
The instant application discloses, among other things, a specific set of cutting proportions tailored for the optical characteristics of Silicon Carbide (“SiC”) which may produce a “Hearts & Arrows” reflection pattern.
This disclosure relates to a way to produce a “Hearts & Arrows” reflection pattern in a transparent Silicon Carbide (“SiC”) gemstone.
BACKGROUNDGenerally, facets on precious and semi-precious gemstones are cut so as to provide brilliance to these gemstones in an economical manner. Gemstones may also be cut to provide reflections with patterns visible.
SUMMARYThe instant application discloses, among other things, a specific set of cutting proportions tailored for the optical characteristics of Silicon Carbide (“SiC”) which may produce a “Hearts & Arrows” reflection pattern.
Silicon Carbide (SiC) is a compound of silicon and carbon. It exists in a number of crystalline forms, often grouped as polytypes of similar structures. Four common polytypes are 3C and 2H (β), 4H, and 6H (α). 3C (β) has a cubic crystal structure; 2H, 4H and 6H (α) each have a hexagonal crystal structure.
An SiC gemstone cut with the angles indicated may display a Hearts & Arrows pattern. One having skill in the art will recognize that slight variations, up to 0.1 degrees greater or smaller, in the cutting angle may still produce the Hearts & Arrows pattern.
The pavilion facets are polished 420, as is the girdle 430. The stone is transferred to allow cutting and polishing of the crown side.
The crown main, star, and girdle facets are cut 450, and polished 460.
Refraction is a bending of light which occurs when the light passes through at least two mediums having a different refractive index, which means that a wave moves at a different speed in one of the mediums than the other. When dealing with gems, light may travel through air and one or more materials in the gem, which may cause refraction. For SiC, light may travel through air, Silicon 710, and Carbon 720.
Silicon 710 has a different refractory index than Carbon 720, which may cause SiC to exhibit birefringence; a ray of light entering an SiC crystal may be split into two rays, one from Silicon 710 and one from Carbon 720. If these two resulting rays are not aligned properly upon exiting the crystal, optimum brilliance may not be obtained. Cutting a table on a plane perpendicular to the C Axis may allow optimal light reflection internally from a gem by ensuring each entering light ray passes through a roughly equal number of Silicon Atoms 710 and Carbon Atoms 720. This may allow a pattern to appear clear, distinct and coherent; it may appear as a single image. Cutting a table other than perpendicular to the C axis may cause a pattern to appear in duplicate, and consequently out of focus and blurred.
While the detailed description above has been expressed in terms of specific examples, those skilled in the art will appreciate that many other configurations could be used. Accordingly, it will be appreciated that various equivalent modifications of the above-described embodiments may be made without departing from the spirit and scope of the invention.
Additionally, the illustrated operations in the description show certain events occurring in a certain order. In alternative embodiments, certain operations may be performed in a different order, modified or removed. Moreover, steps may be added to the above described logic and still conform to the described embodiments. Further, operations described herein may occur sequentially or certain operations may be processed in parallel. Yet further, operations may be performed by a single processing unit or by distributed processing units.
The foregoing description of various embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. The above specification, examples and data provide a complete description of the manufacture and use of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
Claims
1. An SiC gemstone displaying a hearts and arrows pattern, comprising:
- a crown portion, comprising: a table cut perpendicular to a C-axis of the gemstone; a plurality of crown main facets cut at an angle of between 31.81 and 32.01 degrees; a plurality of crown girdle facets cut at an angle of between 38.90 and 39.10 degrees; a plurality of star facets cut at an angle of between 21.36 and 21.56 degrees;
- a pavilion portion comprising: a plurality of pavilion main facets cut at an angle of between 40.60 and 40.80 degrees; a plurality of pavilion girdle facets cut at an angle of between 41.74 and 41.94 degrees; and
- a girdle portion abutting the crown portion and extending along a predetermined plane.
2. The SiC gemstone of claim 1 wherein there are 8 crown main facets.
3. The SiC gemstone of claim 1 wherein there are 16 crown girdle facets.
4. The SiC gemstone of claim 1 wherein there are 8 star facets.
5. The SiC gemstone of claim 1 wherein there are 8 pavilion main facets.
6. The SiC gemstone of claim 1 wherein there are 16 pavilion girdle facets.
7. The SiC gemstone of claim 1 wherein the SiC is selected from a group comprising 6H, 4H, 2H, and 3C SiC.
Type: Application
Filed: Aug 14, 2013
Publication Date: Dec 12, 2013
Inventor: Anthony Ritchie (Kent, WA)
Application Number: 13/966,286