Used in jewelry and cutting tools. Four times as hard as corundum. Diamond 10 Sapphire and ruby are varieties of corundum. Twice as hard as topaz. Corundum 9 The November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8. Topaz 8 Quartz 7 Orthoclase is a feldspar, and in German, "feld" means "field". Orthoclase 6 When you are hungry you have a big "appetite". Apatite 5 Fluorine in fluorite prevents tooth decay. Fluorite 4 Limestone and most shells contain calcite. Calcite 3 Plaster of paris. Gypsum is formed when seawater evaporates from the Earth’s surface. Gypsum 2 Talcum powder. Talc 1 Associations and Uses Mineral Hardness
Hardness of some other items: Hardened steel file 7+ Iron pyrite 6.5 Glass 6-7 Knife blade 5.5 Iron 4-5 Platinum 4-4.5 Copper penny 3 Gold, Silver 2.5–3 Fingernail 2.5
When broken minerals break along planes of weakness
Related to crystalline structure
Some break along 1 plane, others 2 planes
The way a mineral without cleavage breaks
Not all minerals cleave easily
can be smoothly curved, irregular, jagged or splintery.
Specific Gravity is the ratio of the density of a material compared to the density of water 1g/ml. Materials greater than 1 will sink. Materials less will float.
Density of the mineral
4-6 Heavy Cordrundum, most metals 19 Heaviest Gold, platinum 3-4 Medium Heavy Fluorite, beryl 2-3 Medium Quartz 1-2 Light Graphite Specific Gravity Density Mineral