Mineral: Rutile
Locality: Golconda pegmatite, Governador Valadares, Vale do Rio Doce, Minas Gerais, Brazil
Dimensions: 3,5 x 3,0 x 5,0 cm

Description: Main crystal size: 5,2 cm Practically intact group of sharp-edged, lustrous, black crystals in parallel formation with a little contact at the base; chemical analysis shows zonation with a majority of tantaliferous rutile and a niobian rutile core (based on an average of 12 sampling points from the same mine: 22% Ta2O5, 20% Nb2O5, 35% TiO2). MIM number 1168 Photographer: Augustin de Valence (Aïnu)

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