Black tea is made from the leaves of a bush called Camellia sinensis. A process called oxidation turns the leaves from green to a dark brownish-black color. Oxidation means the leaves are exposed to moist, oxygen-rich air.
Marble is a non-foliated metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Geologists use the term marble to refer to metamorphosed limestone; however, stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for sculpture and as a building material.eologists use the term marble to refer to metamorphosed limestone; however, stonemasons use the term more broadly to encompass unmetamorphosed limestone.
Marble is a metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism.nder the conditions of metamorphism the calcite in the limestone recrystallizes to form a rock that is a mass of interlocking calcite crystals. A related rock, dolomitic marble, is produced when dolostone is subjected to heat and pressure. Photo Gallery: The Many Uses of Marble.