BRAZILIANITE
Brazilianite is a sodium aluminum hydroxy-phosphate
mineral, NaAl3(PO4)2(OH)4. It
has a glassy, nonmetallic luster, is translucent to transparent, ranges in
color from clear to yellowish-green to yellowish, has a white streak, good
cleavage, is moderately hard (H = 5.5), and has a conchoidal fracture.
Despite is relative softness, high-quality faceted brazilianite has entered the
gem market. This mineral occurs in phosphate-rich pegmatitic granites.
Brazilianite (olive green) & albite feldspar (white) from the Telirio Mine,
Linópolis, Doce Valley, Minas Gerais State, Brazil (CSM # 53673, Colorado
School of Mines Geology Museum, Golden, Colorado, USA).