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.
Color: Marble is usually a light-colored rock. When it is formed from a limestone with very few impurities it will be white in color. Marble that contains impurities such as clay minerals, iron oxides or bituminous material can be bluish, gray, pink, yellow or black in color. Marble of extremely high purity with a bright white color is very useful.