Do now… • What elements make up Selenite Gypsum? Topic: Identifying Minerals https://www.youtube.com/watch?v=c7w JP_K_sAQ Properties of Common Minerals Earth Science Reference Tables page 16 Look at the last page of ESRT to find the minerals you need to know. On the mineral chart Elements that make up the minerals Tests for Identifying Minerals Test 1: Color Test Test 1: Color Test *Color is a bad property to identify a mineral. Reasons 1) Many minerals have the same color 2) Minerals occur in different colors Test 2: Streak Test the residue left behind on a streak plate • The streak of a mineral is the color of its powder Where is streak on the chart? Look under Distinguishing Characteristics to find streak • Streak Plates Pyrite is a brassy yellow, but in a powder is green-black What is the color of hematite's streak? Test 3: Hardness Test • A mineral’s resistance to scratching • **BEST TEST for Mineral ID Test 3: Hardness Test Test 3: Hardness Test Talc = hardness of 1 Diamond = hardness of 10 Test 4: Luster • The way a mineral shines or doesn’t shine • Our two lusters – Metallic or Non-Metallic Metallic Luster Pyrite, Galena Non-Metallic Luster Quartz (Amethyst), Beryl (Emerald), Corundum (Ruby, Sapphire) Metallic—shines like a metal Either (can be metallic or non-metallic) Non-Metallic— doesn’t shine like a metal Find Hematite on ESRT pg 16 Hematite’s luster is unique: Either The check indicates if a mineral has fracture or cleavage Test 5: Breaking a Mineral 1) Cleavage - breaks or splits along flat planes • Basal Cleavage: Mica • Rhombohedral Cleavage: Calcite 2) Fracture- breaks apart an uneven surface. Rose Quartz.