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Quartz |
Quartz is the second most common mineral in Earth’s crust. It is a member of the quartz group, which includes less common minerals such as opal, crystobalite, and coesite. Silica (Si) and Oxygen (O) are the only elements within pure quartz. If a cooling magma has silica left after feldspars have formed, quartz is likely to form. Because of its low density, even lower than many feldspars, quartz is also like to float in the magma and accumulate in surface rocks. Quartz can be found in all sorts of rocks. Intrusive igneous rocks sometimes contain large quartz crystals. Metamorphic rocks such as gneiss also have large quartz crystals. Sedimentary rocks such as sandstone are often made of tons of little pieces of quartz crystals. In fact, most sand is made of quartz because it is hard and does not weather away easily. Some pieces of quartz are white like milk but most are clear like glass, sometimes with a little pink or grey tinge of color. Quartz
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Find out how to identify minerals (...and learn what shape, luster, color, streak, hardness, cleavage and fracture are all about!)
Meet some other silicate minerals!
Quartz is one of the most common mineral in Earth’s crust! Silica (Si) and Oxygen (O) are the only elements within pure quartz. If a cooling magma has silica leftover after feldspars form, quartz is likely to form. Quartz can be found in all sorts of rocks. Igneous rocks sometimes contain large quartz crystals. Metamorphic rocks such as gneiss also have large quartz crystals. Sedimentary rocks such as sandstone are often made of tons of little pieces of quartz crystals. In fact, most sand is made of quartz because it is hard and does not weather away easily. Some pieces of quartz are white like milk but most are clear like glass, sometimes with a little pink or gray tinge of color. Quartz
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Find out how to identify minerals (...and learn what shape, luster, color, streak, hardness, cleavage and fracture are all about!)
Meet some other silicate minerals!
This mineral is called quartz! Sometimes it looks white like milk but usually it looks clear like glass, sometimes with a little pink or gray tinge of color. You can find crystals of quartz in many different types of rocks. Igneous rocks that form deep in the ground can have big quartz crystals in them. Metamorphic rocks that are made when rocks are squished and heated often have quartz in them too. Often sand is made of little bits of quartz. When all the sand grains get stuck together they make a sedimentary rock called sandstone! |
Find out how to identify minerals!
Meet some other silicate minerals!
