Method and apparatus for simplifying and improving consistency of color grading of gemstones
US5064281A · kind A · utility
Inventor
Key dates
| Filing date | Mar 14, 1991 |
| Grant date | Nov 12, 1991 |
| Priority date | — |
| Expiry date | Mar 14, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/87
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A color grading scale comprises a plurality of individual cast resin chips, each representative of a single color, with the chips attached one to another to form a continuous array of color chips. In a preferred form, the chips are incorporated into a linear slide which fits within a groove formed in a surface of a frame. The frame is formed of a plastic material having a bright white color for maximum white light reflection. Formed in the frame adjacent to and spaced from the groove is at least one shallow pocket having a depth substantially the same as the groove for receiving a gemstone to be color graded by comparison to the color chips of the slide. Plural pockets of different sizes may be provided to accommodate different size stones.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.