SUGILITE
Sugilite is a rare
potassium-sodium-iron-manganese-aluminum-lithium silicate mineral (KNa2(Fe,Mn,Al)2Li3Si12O30).
It has a nonmetallic luster, is typically purplish or lilac or brownish in
color, and has a whitish to brownish streak. Sugilite is fairly hard (H =
6 to 6.5) and only rarely forms decent crystals. The principal locality
for sugilite is the Kalahari Manganese Fields of South Africa.
Sugilite
(purple) from the Kalahari Manganese Fields (Hotazel Formation,
Paleoproterozoic, ~2.2-2.3 billion years) at Kuruman, South Africa.
(Dwyer Mercer County District Library # 422-25,
Celina, Ohio, USA)