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This Is the Rarest Crystal on Earth with Only 50 Known Samples
Initially, taaffeite was confused with spinel, a common mineral that also boasts a stunning range of colors due to the ...
Princeton University10y
Spinel, part 1
Spinel, MgAl 2 O 4 (download cif), is a rare gemstone that was used to imitate rubies. The structure has face-centered cubic symmetry, and is a little heavy to understand. The general formula is AB 2 ...