Aikinite

Aikinite is a sulfide mineral of lead, copper and bismuth with formula Pb Cu Bi S₃. It forms black to grey or reddish brown acicular orthorhombic crystals with a Mohs hardness of 2 to 2.5 and a specific gravity of 6.1 to 6.8. It was originally found in 1843 in the Beryozovskoye deposit, Ural Mountains. It is named after Arthur Aikin (1773–1854), an English geologist.

Aikinite
General
Category	Sulfide mineral
Formula	Pb Cu Bi S3
IMA symbol	Aik[1]
Strunz classification	2.HB.05a
Dana classification	3.4.5.1
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pnma
Unit cell	a = 11.297, b = 11.654 c = 4.061 [Å], Z = 4
Identification
Formula mass	575.92 g/mol
Color	Lead gray, grayish black, reddish brown
Crystal habit	Acicular, massive
Cleavage	{010} indistinct
Mohs scale hardness	2–2.5
Luster	Metallic
Streak	Grayish black
Diaphaneity	Opaque
Specific gravity	6.1–6.8, Average = 6.44
Other characteristics	Not radioactive
References	[2][3]

It has been found in Western Tasmania, in mines located near Dundas, Tasmania.