Chemical Formula: PbFe3+4As3+10O22
Locality: In a boulder of ore found at Tsumeb, Namibia.
Name Origin: Named for mineral dealers Ludlow Smith and Locke Key, who discovered the mineral.
History
Discovery date : 1970
Town of Origin : TSUMEB
Country of Origin : NAMIBIE
Optical properties
Refractive Index: from 1,96 to 2,12
Physical Properties
Cleavage: {011} Perfect, {021} Perfect
Color: Reddish brown.
Density: 4.37 – 4.4, Average = 4.38
Hardness: 1.5-2 – Talc-Gypsum
Luster: Subadamantine
Streak: pale brown
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