Investigating Minerals, Rocks, and Fossils

Investigating Minerals, Rocks, and Fossils — page 9
INVESTIGATING MINERALs Rocks AND Fossus known as building stones They are removed from the earth by a process called quarrying Buried treasure lies in the rocks Some of their minerals are highly valued jewels such as diamonds emeralds and rubies Gold and silver iron copper and the miracle metals of the atomic age uranium and thorium are among the minerals essential to modern civilization These are taken from the earth by mining IDENTIFYING MINERALS AND RoCKS Scientists identify minerals by certain impor tant properties These include hardness cleavage and color Other means of dis tinguishing a mineral are its elasticity and strength specific gravity radioactivity and thermal electrical and magnetic proper ties Luminescence or the emission of light Sometimes permits rapid detection of some minerals including some uranium ores The hardness of minerals is usually stated in terms of the Mohs scale The scale ranks minerals as follows from softest to hardest D talc 2 gypsum 3 calcite 4 fluorite 5 apatite 6 orthoclase quartz 8 topaz 14