Spinel crystallizes
in the cubic crystal systeme, its hardness is about 8. Chemical properties:
A mixture of magnesium-oxide (MgO) and aluminium-oxide (Al2O3).
The magnesium-oxide can also be replaced by zinc-oxide (ZnO), ferrous iron
or manganese.
Spinel is found as water-worn pebbles in USA, Brazil, Thailand and Cambodia. Its colours vary from red, rose-red, blue, violet and green gems to completly black.stones. Due to the fact that spinel, ruby and sapphire look very similar, these two minerals have very often been mixed up in former times, thats also why the Black Prince´s Ruby in the English crown is a spinel. 
In the early 1920´s man began to produce synthetic gem material, and today synthetic spinel is available in all colours and shapes as a cheap replacement of other stones. |
