STONE WITH EMERALD CUT CROWN AND MODIFIED BRILLIANT CUT BASE

• US 3,796,065 A
• Filed: 11/15/1971
• Issued: 03/12/1974
• Est. Priority Date: 12/01/1970
• Status: Expired due to Term

• Current Assignee: Basil Watermeyer
• Original Assignee: Basil Watermeyer
• Inventors: Watermeyer, Basil
• Primary Examiner(s): Shay, F. Barry
• Application Number:
  US05/198,615
• Time in Patent Office: 848 Days
• Field of Search: 63/32 51/283 D45/1,2
• US Class Current: 63/32
• CPC Class Codes: A44C 17/001 Faceting gems

Abstract

A diamond is cut to emerald shape with the conventional crown breaks and girdle. The base of the diamond is formed to pyramidal shape, the pyramid forming about 41* with the girdle plane. Adjacent the girdle base breaks are made at between 52* and 65* to the girdle plane. Between these breaks and the collet pairs of halves are formed with the result that the base breaks acquire a half-moon shape or become lunulae. At the short sides of the emerald cut shape point corners are cut to extend to the apices of the halves. The crux of the matter resides in the base breaks that become lunulae.

Claims

1. A cut diamond having a girdle with at least three long straight sides and an equal number of short sides at the intersections of the long sides so cut as to provide a table, crown breaks of the emerald-cut type and a base which is substantially pyramidal in shape and formed with a collet, characterized in that the base has:

a lunula bordering each said long side along substantially the entire length thereof and corresponding to the first base break of an emerald cut, a point corner extending from each short siDe along the ridges of the base pyramid, two halves to each side of each point corner, and a pavilion penetrating between each pair of halves and having an apex at the boundary of a lunula, each of said halves having a side defined by a side of one of said lunulae and each said pair of halves being bounded by a side of one of said point corners and one of said pavilions.

2. A cut diamond as claimed in claim 1 in which the lunulae are formed on breaks which extend about a quarter of the depth of the base.

3. A cut diamond as claimed in claim 2 in which the lunulae are formed at angles between 52* and 65* to the plane of the girdle.

4. A cut diamond claimed in claim 3 in which the residual pyramidical faces form an angle of about 41* with the girdle and the halves are formed at the same inclination, so that the pavilions and the halves along a ridge have a common apex point spaced from the collet.

5. A cut diamond as claimed in claim 3 in which the girdle has four long sides of equal length to constitute a square cut diamond.