synonym od uranpyrochlore is a radioactive mineral with formula (U,Ca,Ce)2(Nb,Ta)2O6(OH,F) and hardness of 4-5. Is a uranium cacium cerium hydroxy-fluoro-niobate/tantalate.It has a non metallic luster with blackish color. The lower part of the stone is matrix.It comes from South Platte Pegmatite District,Front Range,Jefferson County,Colorado,USA.
Size: 8.6x7.1x5 mm.
Weight: 3.29 ct.