MINERALS Naturally occurring inorganic solid with a chemical

MINERALS Naturally occurring inorganic solid with a chemical composition and a crystalline structure

• Naturally Occurring • Inorganic • Solid WITH A • Chemical and Crystal Composition THE MINERAL MACARENA !!!!!

MATTER PURE SUBSTANCE MATTER Anything that has mass or MIXTURE Contains two or more substances mixed together but not chemically combined volume Made of only one kind of matter Different Atoms ALIKE ATOMS ELEMENT COMPOUND A substance that cannot be broken into simpler substances A substance that contains two or more elements that are chemically combined MINERAL ROCK Naturally occurring inorganic solid with a definite chemical composition and crystal structure A solid substance composed of one or mineral Igneous Rock Forming Metamorphic Ore Forming Sedimentary

THE FIVE (5) CHARACTERISTICS OF A MINERAL

COLOR The color of minerals depends on the presence of certain atoms, such as iron or chromium which strongly absorb portions of the light spectrum. The mineral olivine, containing iron, absorbs all colors except green, which it reflects, so we see olivine as green. All natural minerals also contain minute impurities. Some minerals such as corundum get their colors from these impurities. Blue corundum (sapphire) is formed when small amounts of iron and titanium are dissolved in the solid crystal. Finally some crystals get their color from growth imperfections. Smoky (black) quartz is a good example. Growth imperfections interfere with light passing through the crystal making it appear darker, or almost black.

STREAK The color of a mineral when it is powdered is called the streak of the mineral. Crushing and powdering a mineral eliminates some of the effects of impurities and structural flaws, and is therefore more diagnostic for some minerals than their color. Streak can be determined for any mineral by crushing it with a hammer, but it is more commonly (and less destructively) obtained by rubbing the mineral across the surface of a hard, unglazed porcelain material called a streak plate.

LUSTER The luster of a mineral is the way its surface reflects light. Most terms used to describe luster are self-explanatory: metallic, earthy, waxy, greasy, vitreous (glassy), adamantine (or brilliant, as in a faceted diamond). It will be necessary, at least at first, only to distinguish between minerals with a metallic luster and those with one of the non -metallic lusters. A metallic luster is a shiny, opaque appearance similar to a bright chrome bumper on an automobile. Other shiny, but somewhat translucent or transparent lusters (glassy, adamantine), along with dull, earthy, waxy, and resinous lusters, are grouped as nonmetallic.

BREAKAGE CLEAVAGE: When a mineral cleaves, it often exhibits many cleavage surfaces, but most of these are generally parallel to one another. A hundred cleavage surfaces parallel to one another all define a single direction of cleavage, because all of them are parallel to the same zone of bond weakness. It is the number of directions of cleavage that we record, along with the angles between them. Minerals with two or more cleavage directions generally have a "stair-step" appearance when viewed with a magnifying glass. FRACTURE: When bonds between atoms are approximately the same in all directions within a mineral, breakage occurs either on irregular surfaces (splintery or irregular fracture) or along smooth, curved surfaces (conchoidal fracture), similar to those formed when thick pieces of glass are broken.

HARDNESS Diamond is the hardest mineral, because it can scratch all others. Talc is one of the softest; nearly every other mineral can scratch it. We measure a mineral's hardness by comparing it to the hardnesses of a standardized set of minerals first established by Friederich Mohs in the early nineteenth century, or with the common testing materials that have been calibrated to those standards. The Mohs Hardness Scale is a relative scale. This means that a mineral will scratch any substance lower on the scale and will be scratched by any substance with a higher number. • Diamond The Hardest Known Substance Diamond is the hardest naturally occurring substance known; it is also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications.