Marble is a metamorphic rock that is formed from limestone. Limestone is a sedimentary rock that is composed primarily of calcium carbonate. When limestone is subjected to heat and pressure over a long period of time, it undergoes a process of metamorphism, which causes the minerals within it to recrystallize and fuse together.
During this process, the original structure of the limestone is altered, and it takes on the characteristic veined and swirled appearance of marble. The high temperatures and pressures cause the calcium carbonate crystals in the limestone to grow larger and interlock with each other, resulting in a much harder and more durable rock than the original limestone.
Marble can come in a range of colors, including white, gray, pink, and green, depending on the impurities present in the original limestone. It is a popular building material for its beauty, strength, and versatility.