Properties of Minerals What is a mineral? The Rules of the Mineral       Every Mineral must follow these set of rules Naturally Occurring Inorganic Solid Crystal Structure Definite Chemical Composition Mineral Questions Are pearls considered minerals? • No, because they are made from animals Is naturally occurring glass considered to be a mineral? • No, because it does not have a crystal structure Crystal Structure A crystal is a solid in which the atoms are arranged in a pattern that repeats again and again  Internal Arrangement of the Atoms A tetrahedral site lies in the center of a 4- A tetrahedral site lies in the center of a 4- Definite Chemical Composition  This means that a mineral always contains certain elements in definite proportions  Quartz- always has one atom of Silica for every two atoms of oxygen The Mineral Beryl Emerald Aquamarine The Mineral Corundum  Ruby Sapphire Birthstones January - Garnet July - Ruby February - Amethyst August - Peridot March -AquamarineSeptemberSapphire April – Diamond October - Opal May – Emerald November - Topaz June - Pearl December - Zircon Identifying Minerals Each Mineral has its own specific properties that can be used to identify it Hardness  Color  Streak  Luster  Density  Crystal Shape  Cleavage & Fracture  Special Properties  Streak- the color of a mineral when it is made into a powder  Pyrite(fool’s gold) is very similar in color to real gold, but Pyrite has a greenish-black streak and gold has a gold streak Luster- describes how light reflects off a minerals surface  Metallic Luster- describes minerals that are shiny  Glassy Luster- describes minerals that look like they have a glassy surface, ex Quartz  *Minerals are usually described as having a metallic or non-metallic luster Which mineral has a metallic luster and which has a glassy luster? Crystal Shape   Every crystal has a characteristic shape that is due to its Crystal structure Halite(NaCl or Salt)- will always have six sides and form a cube Hoppered pink Halite crystals from the evaporation Minerals will either break by cleavage or fracture?  Cleavage- a minerals ability to split easily along flat surfaces  Fracture- minerals which break with rough or uneven surfaces Special Properties  Fluorescence- some minerals glow under ultraviolet light ex.) Fluorite  Magnetism- some metallic minerals are naturally magnetic ex.) Magnetite  Effervescence- some minerals such as Calcite fizz when acid is placed on it  Electrical Properties- a few minerals, such as quartz produce an electrical current Fluorite Scheelite(fluorescent mineral) Magnetite Magnetite [...]... the evaporation Minerals will either break by cleavage or fracture?  Cleavage- a minerals ability to split easily along flat surfaces  Fracture- minerals which break with rough or uneven surfaces Special Properties  Fluorescence- some minerals glow under ultraviolet light ex.) Fluorite  Magnetism- some metallic minerals are naturally magnetic ex.) Magnetite  Effervescence- some minerals such as... to real gold, but Pyrite has a greenish-black streak and gold has a gold streak Luster- describes how light reflects off a minerals surface  Metallic Luster- describes minerals that are shiny  Glassy Luster- describes minerals that look like they have a glassy surface, ex Quartz  *Minerals are usually described as having a metallic or non-metallic luster Which mineral has a metallic luster and which... Mohs Hardness Scale 1 = Softest (talc or graphite)  10 = Hardest (diamond)  How do you determine if one mineral is harder than the other?  Perform a scratch test  If the mineral gets scratched it is softer than the object that scratched it Which mineral is gold? How would you be able to tell the difference? Streak- the color of a mineral when it is made into a powder  Pyrite(fool’s... ultraviolet light ex.) Fluorite  Magnetism- some metallic minerals are naturally magnetic ex.) Magnetite  Effervescence- some minerals such as Calcite fizz when acid is placed on it  Electrical Properties- a few minerals, such as quartz produce an electrical current Fluorite Scheelite(fluorescent mineral) Magnetite Magnetite