A trace radioactive element, symbol, Ra. It occurs in uranium ores
A trace radioactive element, symbol, Ra. It occurs in uranium ores
Marine protozoa subject to silica replacement fossilization sound in limestone, shale and other rocks
Lines converging at a single center
Alpha, beta or gamma energy emitted by the decay of atomic nuclei from their radioactive source
The percentage of valuable minerals successfully recovered in ore
An initial exploration and ground survey of mineral lands
The closing and rehabilitation of a mine back to its original or natural state
An ore or arsenic, Arsenic monosulfide.
A heavy, dense, rare element of the platinum group. Symbol, Rh
Rare mineral and metallic elements such as niobium, yttrium, Lanthanum, cerium, praseodymium, neodymium, samarium, thulium, ytterbium, neodymium, dysprosium, gadolinium, promethium, scandium and lutetium