1 Sapphire blue is a cool color. 2  Sapphire carries the blue symbolism of importance and confidence. 3  Although it's not a light or pastel blue, it still has something of a fresh, spring-like quality with a touch of childlike playfulness.
Sedimentary rocks make up only 5% (by volume) of the upper 10 miles of the crust, but about 75% of the outcrops on the continents. Two primary types of sedimentary rocks: 1  Chemical-precipitate from solution (e.g., limestone); most important constituents are calcite, dolomite, chalcedony (SiO2), gypsum, and halite.2  Chemical sedimentary rocks can be further divided as to: 3  inorganic (e.g., limestone, rock salt, dolomite). Chemical-precipitate from solution (e.g., limestone); most important constituents are calcite, dolomite, chalcedony (SiO2), gypsum, and halite. 2  Chemical sedimentary rocks can be further divided as to: 3  inorganic (e.g., limestone, rock salt, dolomite). 4  organic (e.g., limestone or coal).
Gypsum crystals in the Cave of the Crystals in Mexico. Note person for scale. Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 Â·2H 2 O. It can be used as a fertilizer, is the main constituent in many forms of plaster and in blackboard chalk, and is widely mined.he word gypsum is derived from the Greek word Î³ÏÏÎ¿Ï (gypsos), chalk or plaster. Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known as plaster of Paris.