Stone Selection

Thermopolis hot springs Limestone in the making - Thermopolis, WY

Granitedown arrow | Marbledown arrow | Schistdown arrow | Soapstonedown arrow | Limestonedown arrow | Quartzitedown arrow

All granite and marble countertops are made from natural stone that has been quarried from mountains all over the world. As a natural product they are prone to variations in color, pattern and density that actually adds to the beauty and charm of the material. While granite is a hard stone capable of withstanding the harshest of domestic environments, marble is softer (but can be more dense) and can functions better in less used areas. Both materials can be scratched if abused and both can stain if not cleaned up immediately. Additionally, the surface finish selected will affect the properties of the stone selected.

Below is a categorical description of the most common natural stones used in homes. We hope you find this information helpful in making your stone slab selection for your counter tops. You may click on the category headings to see what materials of that category we have in stock here in Denver. Please note all slabs are 3cm unless otherwise noted. Also note that many stones are known by more than one name. Dr. Daniel Pivko has complied tables containing incorrect names and common names (including some material data) of both granites and marbles (these table are sorted alphabetically by the commercial name). It may be easiest to use these tables in conjunction with your browser's "find" function (CTRL+F in Windows browsers).

Granite

What is commercially known as granite includes true granites and gabbro as well as gneiss stones. Granite and gabbro are igneous rock that started out as molten magma and has slowly cooled. The primary difference between a granite and a gabbro is the silica content (gabbro has less silica than granite). Gneiss stones on the other had while resembling granite in it's crystalline structure is actually a metamorphic stone that has metamorphosed from a schist (see section on schists below). These differences (how they were formed, mineral content, density, porosity, etc) are why not all "granite" counters perform the same. However, with proper care & cleaning this should not be an issue in most cases. It may be interesting to note that lighter colored gneiss tend to be less dense than darker stones and true granites. Most of the stone commercially known as a granite are quite hard regardless of their density and will be fairly scratch resistant.

Marble

Marble is simply a evolved form limestone (by a metamorphic process that develops the veining, color, and texture) composed primarily of calcite and dolomite. The coloration of marble is due to the presence of other minerals in the stone. Some minerals and colors they produce are listed in the table below.

Mineral Hematite Diopside Serpentine Limonite
Coloration Red Blue Green Yellow

Some marbles can be as dense or denser than some of the granites. This makes them more stain resistant, however even the densest marbles are not as hard as granites. So marble is more prone to scratches. Also since marble is polished by a chemical reaction, the polish can be removed by chemical reactions. This happens primarily by almost any acid (i.e. lemon juice, vinegar, etc.) and is known as etching. By honing marble the potential of etching can be reduced significantly (especially for lighter colored marbles) and if necessary can be easily buffed out by the homeowner.

Schist

Schists are another a metamorphic stone. However, schists started out as a slate (which metamorphosed from shale and clay) rather than a limestone or sandstone. These stones (schists) can be either medium- and/or coarse-grained and sometimes retain the distinct layering of slate. The layers are less likely (depending on the material) to have a natural cleft than slate however due to the metamorphism that has occurred.

Soapstone

Soapstone is a sedimentary stone composed of talc and chlorite. Chlorite is what gives soapstone it's green coloring, hence the more chlorite present, the greener the stone will look. Talc is the mineral that will, if not oiled dry out causing the soapstone to become flakey. Talc aslo gives the soapstone it's slippery feel. Soapstone is very dense, but also easy to scratch and carve. It is the material of choice for chemisty lab counter tops and also well suited for ornamental carvings.

Limestone/Travertine

Both these stones are sedimentary stones. While limestone is composed primarily of calcium carbonate (>50%) it contains other minerals too. If the magnesium content is >50% then it is considered a dolomite rather than a limestone. Travertine is a crystalline form of calcium carbonate that develops in layers near cold and warm mineral springs. The holes in the travertine are formed from the percolating action of the mineral springs (see picture above). Limestones and travertines can both vary greatly in their hardness, density, and porosity.

Quartzite

Quartzites are also a metamorphic stone, starting out as a sandstone. These materials are primarily quartz with some small amount of other minerals (ie mica & feldspar). Owing to the density, these materials do not readily take an edge detail. For this reason we only offer an eased & polish, 1/4" double or single radius, 1/4" double or single bevel, or a chiseled (broken/snapped) edge finish on these materials.

Local Stone Wholesalers

If you are not able to find the stone you want from our selection here is a list of the local wholesalers where hopefully you can find what you are looking for. We can still quote you a price, but need to know exactly what material you have selected and where you saw it. The reason is that both the size (and therefore the number of slabs required) and our cost (from the wholesaler) need to be taken into account for an accurate bid. Please note this list is alphabetical and in no way imparts a preference nor should it to be deemed complete or exclusive.

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