Crystalline minerals are solid substances that form in a crystalline structure, with atoms arranged in a repeating pattern. BARITE (6 letters) is a mineral composed of barium sulfate, and is often found in sedimentary rocks. DOLOMITE (8 letters) is a carbonate mineral composed of calcium magnesium carbonate. Epidote (7 letters) is a greenish-yellow mineral composed of calcium aluminum iron silicate. CINNABAR (8 letters) is a red or scarlet mineral composed of mercury sulfide. SPAR (4 letters) is a general term for any non-metallic mineral that breaks easily into flat surfaces. QUARTZ (6 letters) is a silicon dioxide mineral that is found in many types of rock. Spinel (6 letters) is a mineral composed of magnesium aluminum oxide. FELDSPAR (8 letters) is a group of minerals composed of aluminum silicates. TOPAZ (5 letters) is a silicate mineral composed of aluminum and fluorine.