Gem Reference
Gem Reference
Black star sapphire is iron-rich, silk-bearing corundum cut in dome cabochons to show a moving white or gold star. Most large commercial black stars are surface-diffusion treated.
Sign in to unlock price ranges by tier, common misidentifications, diagnostic inclusions, treatments, spectra, trade names and sources — free with the GT200 Gem Identification course.
GT200 Gem Identification ↗ Sign inBrowse the free gem reference · Test your eye — the Great Gem Quiz · Singapore gem testing labs
