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Lava is made up of **crystals**, volcanic **glass**, and **bubbles**(volcanic gases). As magma gets closer to the surface and cools, it begins to crystallize minerals like olivine and form bubbles of volcanic gases. When lava erupts it is made up of a slush of crystals, liquid, and bubbles. The liquid “freezes” to form volcanic glass. Chemically lava is made of the elements silicon, oxygen, aluminum, iron, magnesium, calcium, sodium, potassium, phosphorus, and titanium (plus other elements in very small concentrations. Measuring the temperature of [|lava]. Photograph by R.L. Christiansen, U.S. Geological Survey, January 9, 1973.

The temperatures of lavas vary depending on their chemical composition. Hawaiian lava ([|basalt]) is usually around 1100 C. Volcanoes such as Mt. St. Helens erupt lava that are around 800 C.
 * **ock type ** || **Temperature (C) ** || **Temperature (F) ** ||
 * ** [|Rhyolite] ** || **700-900 ** || **1292-1652 ** ||
 * ** [|Dacite] ** || **800-1100 ** || **1472-2012 ** ||
 * ** [|Andesite] ** || **950-1200 ** || **1742-2192 ** ||
 * **Basalt ** || **1000-1250 ** || **1832-2282 ** ||