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Rankamaite Simpsonite & Tantalite-(Mn)

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PDM910410

Rankamaite Simpsonite & Tantalite-(Mn)

Type Locality

Description Tabs

Description
Locality: 
Mumba Cassiterite Gravels, Mumba, Masisi Mountains, North Kivu, DR Congo
Class: 
Crystals on Matrix
Size Range: 
Thumbnail (1-3cm)
Size: 
2.1 × 1.6 × 0.9 cm
Description

A nice size nugget of creamy white fibrous rankamaite, associated to brown simpsonite and tabular blackish tantalite-(Mn). It comes from the Mumba deposits, the type locality from rankamaite.

Historical and very rare piece, collected in the 1960’s by Professor A. Delvaux (1919-1998). Ex A. Delvaux collection.

Combine specimens to reduce shipping costs!.

Mineral Data
What's on the rock

Rankamaite

Formula: 
(Na,K)3(Ta,Nb,Al)11(O,OH)31
Strunz: 
4.DM.05
Crystal System: 
Orthorhombic Water-worn pebbles.
Hardness: 
3.0 - 4.0
Type Locality: 
Mumba cassiterite gravels, Mumba, Masisi Mts, Nord-Kivu, Democratic Republic of Congo (Zaïre)

Simpsonite

Formula: 
Al4(Ta,Nb)3O13(OH,F)
Strunz: 
4.DC.10
Crystal System: 
Hexagonal
Hardness: 
7.0 - 7.5
Streak: 
white
Type Locality: 
Tabba Tabba pegmatite, Wallareenya Station, Port Hedland Shire, Western Australia, Australia

Tantalite-(Mn)

Formula: 
MnTa2O6
Strunz: 
4.DB.35
Hardness: 
6.0
Type Locality: 
Utö Mines, Utö, Södermanland, Sweden

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