This is a beautiful thumbnail size Spinel from Mahenge, Morogoro Region, Tanzania.
Crystal Dimension: 1.8 cm (0.7”) x 1.1 cm (0.4”)
Crystal Weight: 5.8 grams
Spinel is a mineral that owes its beautiful color to chromium, much like rubies and emeralds do.
The chemical formula for Spinel is:
MgAl₂O₄