![]() Dolomite will only effervesce if the mineral is ground up into powder (or if the acid is heated). Calcite (and aragonite) will readily react with acid to form small bubbles (effervescence). Pure samples of dolomite and calcite may have a similar appearance and share many properties, so the easiest way to distinguish them is by their reaction with room temperature dilute acid. Some dolomite crystals also exhibit crystal faces that form slightly curved surfaces, rather than flat planes. Dolomite crystals usually form transparent to translucent rhombs that are colorless to light-colored, although crystals may be red to brown if iron impurities are present. In dolomite crystals, layers of carbonate ions alternate with layers of magnesium and calcium ions, rather than only having layers of calcium ions alternate with carbonate ions as in calcite and aragonite. Dolomite differs from calcite and aragonite in its crystal structure. ![]() Most often found as a massive, white to buff or gray, carbonate rock-forming mineral, dolomite is one of the three most abundant carbonate minerals, calcite and aragonite being the other two. Dolostones that formed from the alteration of limestone rock can retain much of the rock’s original depositional textures, such as fossils, bedding, and other sedimentary features, although sometimes all of this original fabric was lost as the rock recrystallized.ĭescription and Identifying Characteristics These dolostone rocks originally formed as limestone marine deposits on ancient shallow seafloors that were later altered to dolostone as magnesium-rich waters moved through them. By volume, however, most dolomite occurs in its massive form as dolostone or mixed dolostone/limestone sedimentary rocks. ![]() Crystals of dolomite are common in hydrothermal vein deposits and in sedimentary rocks, where they fill pores in their host rock. Dolomite is one of our major sources for the concrete so essential to modern society’s road and building infrastructure. ![]()
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