Zimbabweite

Zimbabweite is a yellow brown mineral with orthorhombic crystal habit and a hardness of 5, with formula (Na,K)₂PbAs₄(Nb,Ta,Ti)₄O₁₈.^[2] It is generally classed as an arsenite but is notable for also containing niobium and tantalum. It was discovered in 1986 in kaolinized pegmatite, i.e. weathered to clay, in Zimbabwe.^[2]

Zimbabweite
Zimbabweite found at its only known locality worldwide
General
Category	Oxide minerals
Formula	(Na,K)2PbAs4(Nb,Ta,Ti)4O18
IMA symbol	Zbb[1]
Strunz classification	4.JA.40
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Ccmb
Unit cell	a = 12.23 Å, b = 15.29 Å c = 8.66 Å, Z = 4
Identification
Color	Yellow, yellow-brown
Luster	Adamantine
References	[2]