THE MINERAL TSUMCORITE

• Chemistry: Pb(Zn, Fe)2(AsO4)2 - H2O, Hydrated Lead Zinc Iron Arsenate
• Class: Phosphates
• Subclass: Arsenates
• Uses: Only as mineral specimens.
• Specimens

Tsumcorite is another mineral that honors the great mineral site of Tsumeb, Namibia. Tsumcorite was first discovered there and is named in its honor. Tsumebite is a phosphate mineral that was also found there and is likewise named for the locality. Tsumcorite forms in oxidation zone of the weathered ore body and is the product of secondary crystallization. As a very rare mineral, tsumcorite is too easy a mineral to identify. Its distinctive color, uncommon yellow streak and a very high density make it very difficult to mistake. The much more common mimetite, which is associated with tsumcorite, is the only thing close, but has a distinctly different crystal habit.

PHYSICAL CHARACTERISTICS:

• Color is reddish brown to yellowish brown or orange.
• Luster is vitreous.
• Transparency: Crystals are translucent.
• Crystal System is monoclinic.
• Crystal Habits include platy or prismatic to acicular crystals and radiating fibrous masses and crusts.
• Cleavage is not observed.
• Fracture is uneven.
• Hardness is 4.5
• Specific Gravity is approximately 5.2 (rather heavy for translucent minerals).
• Streak is pale yellow.
• Associated Minerals are malachite, cerussite, mimetite and other secondary arsenate minerals.
• Notable Occurrence is limited to Tsumeb, Namibia.
• Best Field Indicators are color, crystal habit, density, yellow streak and locality.