Distinguishing natural from synthetic diamond
US5801819A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1997 |
| Grant date | Sep 1, 1998 |
| Priority date | — |
| Expiry date | May 5, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/87
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In order to provide a simple, safe and compact apparatus for distinguishing natural, colorless, or near-colorless diamond from synthetic diamond, the apparatus is equipped with a chamber in which a flash lamp irradiates a stationary diamond with irradiation which has a substantial component of ultra-violet light below 250 nm or 255 nm. The intensity of phosphorescence emitted by the diamond after irradiation by the lamp is measured by a photomultiplier tube which sends a signal to a microprocessor. There is a visual display of the elapsed time for the phosphorescence intensity to decrease to a threshold value. The diamond is classified as probably natural if it has no phosphorescence or a short phosphorescence time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.