Rubies and spinels may show similar colors. One of the simplest ways to distinguish these gems is to test for double refraction with a dichroscope. Since spinels have an isometric crystal structure, they have no double refraction. On the other hand, rubies do have double refraction. Brilliant-cut oval spinel, 6.88 cts, recut by AGTA Spectrum Award-winner Mark Kaufman. Mogok gem tract, Myanmar. © Rob Lavinsky, www.iRocks.com. Used with permission.
Purple Spinel, 6.88 ct Faceted Asscher Cut from Myanmar
Rubies and spinels may show similar colors. One of the simplest ways to distinguish these gems is to test for double refraction with a dichroscope. Since spinels have an isometric crystal structure, they have no double refraction. On the other hand, rubies do have double refraction. Brilliant-cut oval spinel, 6.88 cts, recut by AGTA Spectrum Award-winner Mark Kaufman. Mogok gem tract, Myanmar. © Rob Lavinsky, www.iRocks.com. Used with permission.
Article: Table of Refractive Indices and Double Refraction of Selected Gems
Credit: www.iRocks.com
| Gemstone | Spinel |
| Natural or man made | Natural |
| Origin | Myanmar |
| Origin details | Mogok gem tract |
| Carat Weight | 6.88 |
| Height | 12 |
| Width | 10 |
| Depth | 7 |
| Gem State | Faceted |
| Color | Purple |
| Transparency | Transparent |