Redelijk zeldzame ruwe Manganotantaliet 8 gram ± 4x1x1 cm Origin: Africa Hardness: 6 - 6.5 Specific Gravity: 8.0+ Refractive Index: N/A Chemical Composition: (Fe, Mn)(Ta, Nb)2O6, Iron Manganese Tantalum Niobium Oxide Crystal Structure: Orthorhombic Treatment: None
