Color and streak Color is determined by several factors but its main cause is chemical composition Unreliable for identification Streak is the thin layer of powdered material left when a specimen is rubbed on an unglazed ceramic plate Much more reliable than color for identification
Color and Streak ◼ Color is determined by several factors, but its main cause is chemical composition. ◼ Unreliable for identification. ◼ Streak is the thin layer of powdered material left when a specimen is rubbed on an unglazed ceramic plate. ◼ Much more reliable than color for identification
Hardness and the mohs scale ■ Hardness is a minera’ s relative resistance to scratching. a The mohs relative hardness scale uses ten minerals. each with its distinctive hardness: scale indicate relative hardness
Hardness and the Mohs Scale ◼ Hardness is a mineral’s relative resistance to scratching. ◼ The Mohs relative hardness scale uses ten minerals, each with its distinctive hardness: ◼ scale indicate relative hardness
Mohs relative hardness scale ■10 diamond 9. Corundum 8.Topaz 7.Quartz 6. Potassium feldspar Pocket knife and glass 5.Apatite 4. Fluorite Copper penny a 3. calcite fingernail 2. Gypsum ■1.Talc
◼ 10.diamond ◼ 9.Corundum ◼ 8.Topaz ◼ 7.Quartz ◼ 6.Potassium feldspar Pocket knife and glass ◼ 5.Apatite ◼ 4.Fluorite Copper penny ◼ 3.Calcite fingernail ◼ 2.Gypsum ◼ 1.Talc Mohs relative hardness scale