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Rankamaite With Tantalite-(Mn)

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PDM923626

Rankamaite With Tantalite-(Mn)

Type Locality

Description Tabs

Description
Locality: 
Mumba Cassiterite Gravels, Mumba, Masisi Mountains, North Kivu, DR Congo
Class: 
Crystal Group/Cluster
Size Range: 
Thumbnail (1-3cm)
Size: 
1.7 × 1.3 × 0.7 cm
Description

A nice heavy nugget of creamy white fibrous rankamaite, with granny translucent clusters of quartz. They are associated to tabular blackish tantalite-(Mn) crystals, and some tiny brown grains that could be simpsonite. 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). It comes with a copy of the original label, handwritten by Mr. Delvaux. Ex Albert 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)

Tantalite-(Mn)

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

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