Brilliant-cut stone
Patent 4308727 Issued on January 5, 1982. Estimated Expiration Date: 
August 10, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
August 10, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 946939 1131593 2009390 2447407 InventorApplicationNo. 06/065554 filed on 08/10/1979US Classes:63/32GEMExaminersPrimary: Shay, F. BarryAttorney, Agent or FirmInternational ClassA44C 17/00 (20060101)Foreign Application Priority Data1971-05-28 DEAbstractA jewel of a brilliant type cut is made with facet angles with respect to the girdle plane as follows:(1) A planar table at $c;=0° (parallel of the girdle plane);(2) a pair of angles for one or a plurality of bezel facet rings at $c;1 and a pavilion facet ring at ψ, the pair of angles being within an intransparency triangle. The intransparency triangle is defined in the Cartesian coordinate system y=ψ=0° to 90° above x=$c;=0° to 90° on one side by the straight line $c;=0°, and on the other sides by the transcendental curves (a) &3xb5;o =$c;--ψ and (b) &3xb5;o =180°-3ψ-$c;+ respectively whereby &3xb5;o is the sharp boundary of total reflection;(3) another bezel facet ring at $c;2 with angles between 50° and 90°; and(4) the range of the pavilion facet angles ψ=25° to 51°.Field of SearchGEM | |
