Spinel is a magnesium aluminum oxide mineral (MgAl2O4). It is a member of a larger series of minerals called the spinel group, whose members are gahnite, hercynite, ceylonite, picotite, and galaxite, with the general chemical formula (Mg,Fe,Zn,Mn)Al2O4. Spinel is the magnesium member of the group, also termed by mineralogists as magnesium spinel.

Spinel occurs in all colors of the rainbow. These gems possess beauty, rarity and durability, the necessary hallmarks of a valuable gemstone. Fancy spinels are spinels with colors, such as violet, purple, mauve, lilac, lavender and some blue/green/grey combinations.


In June of 2016, Jewelers of America and the American Gem Trade Association, among the two most prominent organizations in the trade, announced that spinel would be added to the official list of birthstones as an additional birthstone for the month of August, together with peridot and sardonyx.

Spinels are said to extend longevity and to promote love by strengthening the devotion of the wearer to another person and by encouraging passion. Spinels were also used in dark arts to summon demons and protect their wearers from fire.



The common colors of fancy spinels range from Violet (25) to Red Purple (28). Fancy spinels of purple and violet color is mainly due to the presence of iron, cobalt and chromium in the crystal structure. Iron and cobalt are responsible for the blue color, whereas chromium determines the pink and red colors. Violet gems contain lower concentrations of chromium than purple gems.


Fancy spinels are found in MadagascarAfghanistanTajikistan from the Kuh-i-Lal mines, Tanzania and Vietnam.


Variety: Spinel
Species/Series: Spinel Group [(Mg,Fe,Zn,Mn)Al2O4]
Chemical Composition: magnesium aluminum oxide (MgAl2O4)
Crystal System: Isometric
Color: All colors
Refractive Index: 1.718 (+0.017/-0.008)
Specific Gravity: 3.60 (+0.10/-0.03)

For information on other Spinel colors, select Spinel in the Gem Type field.

Properties: SG 3.60 (3.57-3.90) RI is 1.71-1.72, and at times is higher - 1.735 Hardness is 8
Major Sources: Burma, Sri Lanka, Tanzania, Russia (Pamir)
Grading Information: GEM, AAA, AA, A+, A, B
Enhancement Code: NONE
Specific Gravity:3.6