COLORS

Stones are formed by different kinds of natural minerals. Marble, for example, contains predominately calcium in its natural form of calcium carbonate (calcite), and the presence of certain minerals confer marble its shiny coloring. These additional minerals are also responsible for certain colors of granites and other natural stones.

COLOR OF STONE	INVOLVED MINERALS
Black	Biotite (black mica), Hornblende, Carbon
Brown	Limonite (brown iron)
Grey	Different minerals
Green	Mica, Chlorides and Silicates
Red	Hematite (red iron)
White	Feldspar, Calcite and Dolomite
Yellow	Limonite(ore)

MINERAL	MINERAL'S COLOR
Augite	Brown, Green, Black, Purple
Biotite (black mica)	Black, Brown, Green
Calcite	Light colors
Dolomite	Uncolored, Pink, Light brown
Feldspar	Yellow, White, Pink, Green, Grey
Hematite	Metallic grey and Black
Hornblende	Green, Yellow, Brown or Black
Limonite	Black, Brown or Yellow
Sulfur	Pale gold

Minerals have varying crystalline attributes. One of them is the color. If we take Augite, for example, every crystalline state reveals a different color. Shiny colors and different crystal formations of a stone develop when several crystalline properties combine under specific temperature and pressure conditions.

Veins in marbles are the former minerals in fluid state that ran through the stone when the Earth heated up. Intense heat softened the stone and allowed for the liquids to penetrate. After the Earth cooled down, the minerals hardened within the rocks.

The delicate colors in the stones may be altered by using inappropriate cleaning products, chemicals not suited for natural stone or by sun rays. Once more, it is the hardness of the stone that will determine its resistance against these external agents.