Mineral List Most common minerals can be identified by inspecting or testing their physical properties. These properties are color, streak, transparency, luster, hardness, cleavage, fracture, specific gravity, and crystal form. Number is their number on list. 24. Non-Metallic, Dark, Soft, Cleavage. Biotite is a brown mineral characterized by its flaky texture. It is a common mineral in lots of rock, particularly granites, and is visible as small brown flakes. It is also known as mica; biotite and muscovite (which is colorless) are both types of mica. Biotite is sometimes used as a heat resistor and large crystals have been found in 3. Non-metallic, light, soft, cleavage, HCL Test Calcite is usually a white or colorless mineral with crystals that are sometimes shaped like dog's teeth (hence the alternative name dog tooth spar). However the crystals can take lots of different forms and the color is very variable. 6. Non-metallic, Light, hard, cleavage, color-pink H=6, salmon pink color is typical, perthitic intergrowths are common, 2 directions of cleavage at 90 degrees, similar properties to plagioclase Orthoclase is one of the most common minerals, and occurs in numerous mineral environments. It is polymorphous with Microcline and Sanidine. These three minerals form the Potassium Feldspar group. They are almost identical in physical properties, and it is sometimes impossible to distinguish one another without x-ray analysis. The only difference between them is their crystal structure. Microcline crystallizes in the triclinic system, and Orthoclase and Sanidine crystallize in the monoclinic system. Sanidine forms at high temperatures and has a disordered monoclinic symmetry, whereas Orthoclase forms at low temperatures and cools slowly, forming more ordered monoclinic crystals. Non-metallic, light, hard, cleavage H=6, white or gray color, striations may be seen on cleavage surface, 2 directions of cleavage at 90 degrees, similar properties to orthoclase Non-metallic, light, soft, cleavage H=4, 4 directions of cleavage, often purple in color (can be white, clear, yellow, green). Perfect cleavage, hardness, and crystal habits. Fluorite comes in basically every color, although pure Fluorite is colorless. The color variations are caused by various impurities, which are usually hydrocarbons. The hydrocarbons, and thus the coloring, can be removed from a specimen by heating. 11. Metallic, Dark, cleavage Galena forms many interesting crystal shapes. Some cubic crystals have their edges cut by the partial octahedral growth, some octahedral crystals have their points flattened by cubic growth, and many crystals are found somewhat in-between cubic and octahedral. Dodecahedral growths may partially be found in octahedral or cubic-octahedral crystals, resulting in bizarre and interesting shapes. Gray, metallic mineral, 3 directions of cleavage (cubic) 30. Non-metallic, dark, hard, non-cleavage The Garnet group contains closely related, isomorphous minerals that may intergrow or contain a slight percentage of another element found in a different garnet member replacing one of its own. The common garnets can be divided into two classifications: Typically reddish brown color, no cleavage, commonly found in twelve-sided crystals (dodecahedrons) 18. Non-metallic, light, soft, cleavage, salty taste. "Salt", H=2.5, cannot be scratched with a fingernail, 3 directions of cleavage (cubic), salty taste Halite is extremely common. It is found in solid masses, and as a dissolved solution in the oceans and many inland lakes. The inland lakes that are rich in salt exist in arid regions, and are commonly below sea level without an outlet. In many of them there is more water being evaporated than the amount coming in, causing a recede in the water level of the lake and an increase of salinity content 21. Non-metallic, light, soft, cleavage. Lepidolite is an uncommon mica and has only in the past decade become available on the mineral market in large quantities. Lepidolite is an ore of lithium and forms in granitic masses that contain a substantial amount of lithium. The lithium content in lepidolite does vary greatly however and low lithium lepidolite is nearly useless as an ore of lithium. The typical violet to pink color of lepidolite is characteristic and is the only field test available to identify lepidolite from other micas. Pink muscovite or very pale lepidolite may confuse an identification. Lepidolite, like other micas, has a layered structure of lithium aluminum silicate sheets weakly bonded together by layers of potassium ions. These potassium ion layers produce the perfect cleavage. lepidolite crystals accompany such other lithium bearing minerals such as tourmaline, amblygonite and spodumene and can add greatly to the value of these specimens. A rock made of granular pink lepidolite and red to pink tourmaline is used as an ornamental stone for carving. Single large plates or "books" of lepidolite can have appealing violet color and make attractive mineral specimens. 37. Non-metallic, dark, soft, no cleavage, bright green. Malachite is a secondary copper mineral found in oxidized copper deposits. The massive, botryoidal, reniform, and stalactitic forms are dense intergrowths of tiny, fibrous needles. Such specimens are virtually always internally banded in different shades of green, and can be seen when a specimen is polished or cut open. These bands give much interest to this mineral as an ornament, owing to its popularity. 23. Non-metallic, light, cleavage, Mica Clear or translucent color, one perfect direction of cleavage resulting in the mineral pealing into thin, flexible sheets, similar properties to Biotite 28. Olivine
The Olivine group is composed of three minerals, with the following formulas: 22. Metallic, Dark, no cleavage. pyrite is also known as fools gold. Pyrite is a common mineral which can have cubic or octahedral crystals with the crystal faces often having striations (lines across them). It forms in lots of different rocks as a result of a variety of processes and occasionally replaces or coats fossils, leaving fantastic gold-colored shells and fish. 34. Non-metallic, light, hard, no cleavage, pink. Pink variety of Quartz. Rose Quartz is almost always massive, rarely occurring in crystals. Scientifically, there is no reason why Rose Quartz does not occur more commonly in crystals; this remains a scientific mystery. Rose Quartz crystals are thus extremely valuable. H=7, conchoidal fracture, no cleavage, color is typically white or clear but can be pink, red, purple, black 7. Non-metallic, light, hard, no cleavage, clear Quartz is the most common mineral on earth (second most common if Water is considered a mineral). It occurs in basically all mineral environments, and is an important constituent of many rocks. Quartz is also the most varied of all minerals. It occurs in all different forms, habits, and colors. There are more variety names given to Quartz than any other mineral. H=7, conchoidal fracture, no cleavage, color is typically white or clear but can be pink, red, purple, black 15. Metallic, light, soft Colorless, transparent or lightly colored variety of Gypsum. Some people refer to Selenite as a synonym of Gypsum, or as a crystalline variety. Satin Spar 16. silky, translucent, fibrous
10. Non-metallic, light, Hard, cleavage Vitreous, silky, Transparent to opaque, Spodumene is strongly pleochroic. The pleochroism is easily observed in many transparent crystals, where the color ranges from yellow to violet when viewed at different angles. 1. Non-metallic, light, soft, cleavage, silky H=1, very soft, easily scratched by fingernail, 38. Hematite – Not on Test, I just love Hematite
Much information and pictures from http://www.minerals.net/ See Rock List Information and images gathered by www.angelstarcreations.com |
||||||||||||||||||
Click to Visit |
