Marble Rock

That means it can form by rising temperatures and pressures, or by heat only.



The main mineral it consists of is calcite (there is also a dolomitic version that consists of dolomite).

Other minerals - impurities - include quartz, mica, pyrite, iron oxides and graphite.

 

More rarely sphene, tourmaline, epidote, zoisite, spinel, garnet, albite, labradorite, tremolite and/or diposide can also be present.

 

So unless it's white and consists of calcite only, some impurities are giving it a different colour.

 
 By Par_e via Flickr.com

It is formed at high temperatures and low to high pressures.

 
 By philaLAB via Flickr.com

It has a crystalline structure and it is soft, much softer than quartz, which can look similar. It has a fine to coarse texture.

  
 By David Fielding via Flickr.com

It forms from limestone (or dolomite - the dolomitic version).

 
 By Bryan Lee via Flickr.com

It is easy to distinguish from quartz by trying its softness or testing it with HCl - it reacts to the acid.

  
 By Wally Gobetz via Flickr.com

Due to its softness it is perfect to sculpture and has been sculptured since ancient times.

  
 By Bart Everson via Flickr.com

It is also widely used in buildings and countertops, tabletops etc.

 
 By Quinn Dombrowski via Flickr.com

A famous building built from marble is Taj Mahal in India.