SAPPHIRE CRYSTAL (13 mm CORUNDUM)

Corundum is a crystalline variant of aluminum oxide (Al2O3) that often contains small amounts of iron, titanium, vanadium, and chromium. This mineral is significant in rock formation and is naturally transparent, though its color can vary based on the presence of transition metal impurities within its crystal lattice. Corundum is primarily recognized for its two gem varieties: ruby and sapphire. Rubies are characterized by their red hue, attributed to chromium, while sapphires can display a spectrum of colors depending on the specific transition metal involved. A unique type of sapphire known as padparadscha is distinguished by its pink-orange coloration. The term "corundum" originates from the Tamil-Dravidian word kurundam, which translates to ruby-sapphire, and is reflected in its Sanskrit form, kuruvinda.

Under Long Wave UV the crystal turns red/orange.

From "Schneider's Rocks & Minerals, 3021 POWAY", 1991