All about marble

 

What is marble,  limestone and travertine?

What is marble?

 

Marble is a metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite (a crystalline form of calcium carbonate, CaCO3). It is extensively used for sculpture, as a building material, and in many other applications.

Limestone and marble begin as the same material. Marble is simply changed limestone, or to use the technical term, metamorphic limestone.

 

What is Limestone?

 

Limestone is the result of millions of years of sea shells and bones of sea creatures settling as sediment on an ocean floor (hence it is called a sedimentary stone). The calcium in the bones & shells combines with Carbon Dioxide in the water to form Calcium Carbonate, which is the basic mineral structure of all limestone and marble. Less than 3% of the stone is the color, which is simply other natural elements present when the stone formed (ie iron deposits give you a reddy brown).


Given enough heat and pressure, limestone will crystallize, resulting in marble. The crystal structure allows marble to take a polish, and bring out the color of the other trace elements. Limestone, not being crystallized, will not polish.

 

What is travertine?


Travertine began as limestone, which over time, through geological shifting, has found its way deep in the Earth. The porous nature of limestone makes it a great reservoir for liquids. Aquifers, which are the enormous underground pools of water that feed our wells and water our cities, are the remnants of ice age melting, which sank below and was absorbed by limestone. Heated by the Earth’s inner core, the water rises as steam and hot pressurized water, to form hot mud baths, “Old Faithful”, ” Mammoth Springs”, and other gizers. This rising hot water, disolves the limestone and brings with it granules from below, forming mud beds on the surface. If enough time transpires, and the mud beds cool, they will crystallize into solid stone called Travertine.

 

What is honing and polishing?


Stones are polished by diamond studded pads which are applied with pressure and usually water and some thick compound to keep the stone cool. The amount of pressure, the type of pad, the grain count of the diamonds (like the grain count of sandpaper), and the liquid mediums all depend on the particular characteristics of the stone.


Honed finishes are smooth, like a polish, but are non-reflective. This can be achieved three ways:

  • using a stone which cannot polish, no matter what you do.
  • grinding a stone until it is smooth, but stopping just before each crystal achieves a perfect surface.
  • removing an existing polish by applying acid to corrode the surface.

 

What is flamed and sawcut?


Flamed, or sometimes called thermal, is a molten surface which is the result of applying direct flame at high temperatures (a blow torch). This usually is seen in granites and some limestones. Most stones cannot withstand this treatment.


Sawcut finishes are the most unfinished, since this is the surface of the stone when it is first cut, without any treatment. It is a slightly rough surface, usually with circular saw cut marks. Most tumbled marble is made from sawcut material, and if not tumbled quite enough, will still show a bit of this finish. One rarely sees sawcut material sold directly to the consumer.

 

What is bushhammered?

Bushammering is performed with a bush hammering machine with diamond heads. The diamond heads hammers the marble to create dents in order to create a rustic appearance to the marble. The density and the depth of the dents can be adjusted as requested by the customer.

 

What is regular cut and cross-cutting?


Cross-cutting is way of cutting the travertine block. Usually, the travertine is cut vertically in the direction of the vertical lines which form the natural texture of the stone. A regularly cut travertine block exposes the line patterns of the stone.


Cross-cutting is the horizontal cutting of travertine blocks, against the vertical lines forming the natural texture of the stone. Cross-cut travertine blocks have the appearance of beige marble, with a consistent texture. Nowadays, cross-cut travertine tiles are very sought after by architects in the United States.

 

What is filling?


After honing the travertine, the natural pores of the stone are filled by using a filling machine, with a combination of cement, caolin ve color additive to match the natural color of the stone. After the filled stone dries, another honing process is applied.

 

What is tumbling?


The tumbling process consists of mixing marble, sand and pebbles in a large cauldron to create a rustic appearance to the marble.