What is Onyx?

Onyx is quartz crystals fused together by nature into translucent layers of stone, revealing a rainbow of colours ranging Form creamy whites, gold’s and ambers to orange, reds, browns deep greens, and greys. Onyx is not a new stone; It is actually millions of year old! A natural process of heat and pressure creates a crystalline stone rich in color and pattern that reaches well below the surface to reveal a truly unparalleled inner warmth, depth and opalescence.

What is Marble?

Marble is a rock widely used in buildings, monuments, and sculptures. It consists chiefly of calcite or dolomite, or a combination of these carbonate minerals.

What is Travertine?

Porous or crystalline mineral form of calcium carbonate, deposited in layered formations by hot and cold spring waters. The compact crystalline variety of travertine has been used as building stone since ancient Roman times. Massive deposits occur near Tivoli, Italy.

Properties

Marble is formed from limestone by heat and pressure in the earth's crust. These forces cause the limestone to change in texture and makeup. This process is called recrystallization. Fossilized materials in the limestone, along with its original carbonate minerals, recrystallize and form large, coarse grains of calcite.

Impurities present in the limestone during recrystallization affect the mineral composition of the marble that forms. At relatively low temperatures, silica impurities in the carbonate minerals form masses of chert or crystals of quartz. At higher temperatures, the silica reacts with the carbonates to produce diopside and forsterite. At extremely high temperatures, rarer calcium minerals, such as larnite, monticellite, and rankinite, form in the marble. If water is present, serpentine, talc, and certain other hydrous minerals may be produced. The presence of iron, alumina, and silica may result in the formation of hematite and magnetite.

The minerals that result from impurities give marble a wide variety of colors. The purest calcite marble is white. Marble containing hematite has a reddish color. Marble that has limonite is yellow, and marble with serpentine is green.

Marble does not split easily into sheets of equal size and must be mined carefully. The rock may shatter if explosives are used. Blocks of marble are mined with channeling machines, which cut grooves and holes in the rock. Miners outline a block of marble with rows of grooves and holes. They then drive wedges into the openings and separate the block from the surrounding rock. The blocks are cut with saws to the desired shape and size.

Uses:

Marble has long been highly valued for its beauty, strength, and resistance to fire and erosion. The ancient Iranian & Greeks used marble in many buildings and statues. The Italian artist Michelangelo used marble from Carrara, Italy, in a number of sculptures. Marble from Tennessee was used in parts of the National Gallery of Art in Washington, D.C. The Lincoln Memorial, also in Washington, was built of marble from Alabama, Colorado, and Georgia.

Extremely pure calcite marble is used for most statues. This kind of marble is translucent--that is, light penetrates a short distance below the surface of the marble before it is reflected. Large blocks of colored marble are used for columns, floors, and other parts of buildings. Smaller pieces of such marble are crushed or finely ground and used as abrasives in soaps and other products. Crushed or ground marble is also used in paving roads and in manufacturing roofing materials and soil treatment products.

What is Granite?

Granite—The Earth’s Oldest Building Material

Granite is—quite literally—as old as the earth. It is formed from liquid magma, the molten rock still found at the core of the planet, cooled slowly to form a substance approaching the hardness and durability of diamond. Granite is an igneous rock, the name reflecting its fiery beginnings. The chemical composition of granite is similar to that of lava. However, granite owes its hardness and density to the fact that it has been solidified deep within the earth, under extreme pressure. Over the eons, seismic activity has changed the crust of the planet, forcing veins of granite to the surface. Glaciers scraped off layers of dirt, sand and rock to expose granite formations. Typically revealed by outcrops, the deposits have been discovered on all the continents.

Composition

"Granites are formed of an aggregate of crystals which are molded together without any interspace between them or which enclose one another. The magnificent crystallinity of granite is a striking characteristic." Geology of Granite, E. Raguin, London, 1965 p.3

It is accurate to speak of "granites," because many varieties of the stone exist. While they differ in color, texture and crystalline structure, the granites have three essential minerals in common:

· Feldspar (50% or greater)

· Quartz (25-40%)

Mica (3-10%)

These minerals occur in different proportions, giving each granite its own color, texture and structural characteristics. In addition, hornblende, magnetite, hematite, pyrite, zircon, garnet, corundum and other minerals may be present in smaller amounts, adding to the unique coloration and texture of each granite deposit. In supplying granite for all large building or complex of buildings, it is essential that the stone be consistent in color and texture. To assure this, each granite color must be quarried from the same deposit. With natural material like granite, a certain amount of "movement" or grain in the stone must be expected. Many people find this flow and blending of colors to be the most compelling reason for using granite.

If you like more information: http://en.wikipedia.org/wiki/Main_Page