Uraninite, Rutherfordine, ‘Gummite’: Uluguru Mountains, Tanzania

Description

Species: Uraninite, Rutherfordine, ‘Gummite’

Locality: Uluguru Mountains, Morogoro Region, Tanzania

Dimensions: 2.5 x 2.5 x 2.3 cm. (40 grams)

Ex. David P. Wilber Collection

The Uluguru Mountains of Tanzania area a remote but classic locality for rare uranium minerals, which occur in pegmatites here. This is a killer example of LARGE and well-formed cubic uraninite crystals which are being replaced by rutherfordine (Uluguru is the type locality for this mineral) and “gummite.” Measures ~150,000 CPM on my Ludlum Model 3 Counter with 44-9 probe. Rare!!