Answer:
Marble is a metamorphic rock that forms when limestone or dolostone is exposed to high heat and pressure without undergoing melting. The heat and pressure causes the molecules (primarily calcite) to rearrange, forming a more tightly interlocking matrix. Impurities in the parent rock, such as surpentine or iron oxide, cause the characteristic banding that marble is famous for. Unfortunately, marble is not a very durable rock. Since it is composed primarily of calcite or dolomite, it is susceptible to acid erosion. This is often evident in cemetaries, where granite headstones remain sharp far longer than marble ones. Marble can be identified using a dilute HCl solution. Fizzing indicates calcite marble. Fizzing only occurs to dolomitic marble when acid is applied to the marble when powdered.