Onyx Stone

What is Onyx

Onyx is a banded variety of chalcedony which also includes carnelian, agate, bloodstone, etc . The colors of its bands range from white to almost every color (save some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white. The name comes from the Greek word onyx which means nail of a finger or claw. Legend says that one day while Venus was sleeping Eros/Cupid cut her fingernails and left the clippings scattered on the ground. Because no part of a heavenly body can die, the gods turned them into stone which later became known as onyx. Onyx is an extremely variable stone with heavy veining. No two pieces of onyx are ever exactly alike, and one slab might contain dozens of colours.
Onyx is formed from carbonate minerals that are dissolved when dolomite sediments or limestone have contact with hot water. Heat from volcanic activity helps the onyx to form.onyx refers to layered stones and usually this material is cut from agates or other chalcedonies with even parallel layers, mostly with a lighter layer above a darker one.Onyx may be a multilayered black and white stone, usually with a black base and a white upper layer. But it may also be brown and white, as in sardonyx; or red and white as in carnelian onyx. Originally, almost all colors of chalcedony from white to dark brown and black were called onyx (SiO2 with impurities). Today when we think of onyx we often preface the word with black to distinguish it from other varieties of onyx that come in white, reddish brown, brown and banded. A variety of onyx that is reddish brown with white and lighter reddish bands is known as sardonyx. Other names have been used over time for this material, such as "Mexican Onyx" and "onyx-marble".
This natural stone has gorgeous, translucence, and different colors. The colors of onyx are soft and sumptuous, almost delicate look. The light shades of golden honey, mint greens, and whirl browns will give you erotic feel. There are various bands or lines of complementary color running all thorough the stone contributing to its exclusive color characteristics. Onyx is an image feast for the eyes.
Onyx is available in different sizes and shapes. It is a hard stone, which is moderately resistant to damage and measures 7.0 on Moh's hardness scale.Onyx slabs are not as large as granite slabs are, because the material is much more fragile and unlikely to be extracted in such a large block. The slabs almost always have a fiberglass material on the back to hold the stone together. Natural lines are very common in Onyx and don’t represent cracks, as many people can state. Similar to marble, onyx could be completed with a polished surface. This is a silken and reflective base finish that deepens the color and contrasts within the stone. It could also be completed to a honed surface finish that is a dull like low sheen finish. It's not reflective and glossy like a polished finish.

Uses of Onyx

Onyx is formed from quartz, and is the most common type of mineral in the world, accounting for 12 percent of the Earth's crust. Onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items. Use of sardonyx appears in the art of Minoan Crete, notably from the archaeological recoveries at Knossos. Onyx is also mentioned in the Bible at various points, such as in Genesis "and the gold of that land is good.
Black Onyx is often used as a backdrop in jewelry. It is also used as cabochons and as a building material. It has a long history of use for hardstone carving and jewellery, where it is usually cut as a cabochon or into beads. It has also been used for intaglio and hardstone cameo engraved gems, where the bands make the image contrast with the ground. Some onyx is natural but much of the material in commerce is produced by the staining of agate.
Backlighting an Onyx or Precious Stone slab creates a dramatic effect in the room. Use light panels or LED sheets that provide uniform lighting with no hot or cold spots. You may also manipulate the colors of the onyx slab by using different colours of light. Onyx and Precious Stone are perfect for vanity tops, walls or floor features, island front panel, bar tops, splashbacks, etc. For kitchen bench tops, however, require special care, as they tend to absorb liquids quickly and scratch easily. Onyx could also used for novelty items such as vases, urns, wine goblets, lamps and bowls. It really works wonderful
Onyx marble has excellent uses. Onyx marble is used most often as a fireplace surround; bar top, or as a small island as it transmits light. It is also used as cabochons and for building material.

Physical Properties of Onyx



Diaphaneity (Transparency):

Translucent, Opaque


Vitreous when polished


Black and white


often produced by dying agates



Hardness (Mohs):

6½ - 7



Density (measured):

2.6 - 2.65 g/cm3


varies with amount and type of impurities


Chemical Properties of Onyx



Simplified for copy/paste:


Essential elements:

O, Si

All elements listed in formula:

O, Si

Travertine Stone

What is Travertine

Travertine is a white massive concretionary form of calcium carbonate, CaCO3 which is formed by calcium carbonate dissolving in ground water and then being deposited on the earth’s surface by rivers, natural springs, or geysers. One of the most versatile, durable and elegant looking floor cover is none other than the one made from travertine. Travertine is part of the larger group of stone known as limestone (or calcium carbonate). This type of stone is formed when subterranean water sources collect mineral deposits over thousands of years, eventually producing a smooth, porous stone. Travertine is derived from limestone that has been heated and then propelled through the earth by water.
Travertine is usually hard and semi crystalline. It has a layered appearance and in pastel shades of almost beautiful colors and banded as a result of the iron compounds presence or some other impurities. Generally travertine is less coarse-grained and takes a higher polish than stalactite or stalagmite whose chemical composition and origin are similar. Although referred to as "Onyx" in commercial trade, it has the hardness of calcite that is much softer than real Onyx which is a black and white banded agate. In hardness, travertine is similar to marble. travertine tiles come in a variety of shades and finishes
One of the key differences between travertine and other types of stone used for flooring is that it is considered to be a material that is less slippery when wet, providing better grip and less loss of friction. travertine is often used in the high-traffic areas of hotels, casinos and shopping malls due to its reliability and trustworthiness under wet conditions.

Processing travertine tile

Travertine is removed from the earth in large blocks before it is cut into what can be recognized as travertine tile. It may be cut in any of the following ways:


 The travertine is cut with the grain of the stone bedding and on the same layer as it is formed in the earth. This makes for a more uniform texture and color

Vein cut  

the travertine is cut across several layers of the stone bedding, making for a more mottled, tiger-stripe effect when cut into tiles.
After the travertine is quarried, it is strictly selected for color variances, and further assessed after it is cut for holes and chipped edges.

Travertine Types

Generally, there are four different styles or finishes that you can find in travertine tiles :

Polished Travertine Tiles

Probably the most flat and shiny piece of tile, hence its surface is highly reflective and smooth. It is among the best in quality of travertine tiles because polished tiles are only made from the hardest travertine and they are almost stain resistant. However for a number of reasons, polished tiles are not a good choice for flooring, especially for family with children around because they can become very slippery when they are wet.

Filled and Honed Travertine Tiles

These tiles have the same smooth and flat surface but not as shiny. Instead, they are more of a matte finish. In the manufacturing process, most holes and pores of this natural stone are filled. This makes them more resilient to stains and thus less maintenance is required. Though it does not look glossy, it is still slippery when wet. Most of the time, they are used in the floor and wall of home kitchens, bathrooms and showers.

Tumbled Travertine Tiles

A more decorative style of tiles with rounded edges that is available in various sizes and colors. Usually, this tile is left unfilled after the tumbling process and this gave it a rustic look. Unfilled tiles are regularly used as driveway pavement and patio walkways, while filled ones are great for floors and backsplashes in the kitchens and bathrooms. Due to its rough surface, they are good for paving around the pool too.

Chiseled and Brushed Travertine Tiles

Similar to tumbled tiles, only that the sides of these tiles are chiseled away providing it a highly classical and antiquated look. They are great to be installed on both outdoors and wet areas. Outdoor travertine tiles can be left unfilled as long as they are not exposed to acidic spillage

Travertine Uses

Travertine tile remains to be a highly diverse natural stone, suitable for all kinds of applications. History teaches us that there are no limits when it comes to the usage of Travertine stone .Travertine is a common material used in construction, and also nature has her own uses for the calcite deposits. Travertine tile is used as floor tile in both residential and commercial settings, as well as a decorative option for wall cladding and backsplashes. Not only is this natural stone popularly used to tile and decorate the floor, they look just as appealing when being installed on the walls, backsplashes and on kitchen countertops as well. Travertine tile has both indoor and outdoor uses, being a durable stone, and can be both functional and aesthetically striking .Travertine tiles that are installed properly can be long lasting and will not chip or crack easily. Travertinewas used in the ancient world, but can also be found as a major component of many modern buildings.
In addition, there are examples of complete "structures." Tonto Natural Bridge, located in central Arizona near Payson is believed to be the world's largest natural travertine bridge. "The bridge stands 183 feet high over a 400-foot long tunnel that measures 150 feet at its widest point," reads the Arizona State Parks website. Even before Christ, Travertine used to be among the top building stones in Ancient Greek and Rome. Romans took advantage of Travertine for various constructions projects such as buildings and temples, aqueducts, baths, stairs, steps, and amphitheaters such as the Colosseum, the largest building in the world constructed mostly of travertine.

Some of Travertine Uses :

The compact crystalline variety of travertine has been used as building stone since ancient Roman times.

  • Jewellery, like pendants and brooches
  • Bookends
  • Paperweights
  • Carvings like in chess sets

Physical Properties of Travertine

Light transmission

Typically subtranslucent in all but extremely thin pieces


Dull to pearly or even subvitreous.


Effervesces with dilute HCl.


3-4 Moh's scale


Colorless, White, Pink, Yellow, Brown





Specific gravity


Chemical Properties of Travertine

Flash point

89°F / 31°C


In water : at 68°F / 20°C : insoluble


In solvents : soluble in many organic solvents like benzene hydrocarbons and chlorinated hydrocarbons, acetone, phthalates,methanol ,ethanol e.t.c.

Granite Stone

What is Granite

Granite is a hard igneous rock having a coarse-grained surface, chiefly composed of four minerals including  quartz, alkali feldspar, plagioclase feldspar, and hornblende .The word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a polycrystalline rock. The term 'granite' also applies to a group of intrusive igneous rocks with similar textures and slight variations on composition and origin. . It is visibly homogeneous in texture. This unique and elegant natural stone is one of the oldest, hardest, and strongest stones available. A truly beautiful natural stone with hundreds of colors and patterns to choose from. The minerals provide the different colors to the granite that it possesses. It ranges in color from pink and red to light or dark gray or a mix of these. It is generally uniform in color and has high compressive strength and abrasion resistance.
The geological definition of granite is "any plutonic rock in which the mineral quartz makes up 10 to 50 per cent of the felsic components, and the ratio of alkali to total feldspar is between 65 and 95 per cent."Granite being an igneous rock, is formed from the process of magma cooling. This magma, which cools far below the earth's surface at a slow and steady rate, results in the expansion of the aforementioned minerals to a level that they can be conveniently seen with naked eyes. An important thing about granite is that it is not a homogeneous rock, thus its chemical properties vary according to its location.
Some granites change relatively little with changes in temperature. Which also makes granite a good choice for high precision applications that require little change due to temperature.
Flexural strength, or the ability to resist bending force. Makes granite a good material for load bearing applications.Granite is also resistant to many acids and other caustic chemicals. So it is often used as a liner in commercial vats and such. This also makes granite good for applications that are below grade in contact with soil and water.

Granite Uses

Granite common finishes include polished, honed, or thermal. Polished granite tiles are suitable for kitchen and bath walls, floors, or countertops. While granite holds its polish longer than marble and is not bothered by mild acids, such as orange juice or vinegar, over time the traffic on a kitchen floor will dull the finish. Use of doormats and frequent sweeping to remove abrasives from the floor will help prolong the finish. Re polishing the granite tends to be expensive due to the hardness of the material. Waxing and special coatings may help protect the polished finish, but frequent stripping and reapplication can, by itself, cause excessive wear. Another option for floors are honed or thermal finished granite tiles, which are more commonly used outdoors. These are less slippery when wet than polished granite. However, a sealer is required with this type of finish to prevent staining during grouting and to protect from oil or grease stains. These finishes are easy to apply and do not need stripping for touch-up reapplication.
Due to highly dense grain, it is impervious to stain. Polished granite slabs and granite tiles have achieved a special status as building stones globally. Granite is also used for wall cladding, roofing, flooring, and a variety of other interior and exterior applications. Granite is the hardest building stone, and granite slabs and granite tiles occupy a prominent place among dimensional stones. Due to its hardness, resistance to weathering, capability to take mirror polish, fascinating colors and textural patterns, granite slabs and granite tiles are extremely popular. The principal characteristics of granite also include high load bearing capacity, crushing strength, abrasive strength, amenability to cutting and shaping without secondary flaws, ability to yield thin and large slabs and - above all - durability. Traditionally the main use of black granite is in tombstones and other monumental items, and to a lesser extent for various types of counters, especially in the financial world, decorative applications, elegant trimmings and luxury floorings.

Physical Properties of Granite

Physically, commercial granites are Hard, Compact rocks with fine to coarse grains of metamorphic or igneous origin.


6 to 7 on Moh's Scale


2.6 to 2.8 Kg/cm3

Compressive Strength

140 to 210 N/mm2

Modulus of Rupture

15 to 25 N/mm2

Water Absorption


Average Wear

Less then 1%


Quite low

Weather Impact



Chemical Properties of Granite

Chemically, they are igneous/metamorphic rocks composed of quartz, feldspar & ferromagnesian minerals like kriolite, chlorite, garnet, etc. A typical granite will have following chemical composition.

Silica (SiO2)





Less then 0.5%

FeO + Fe2O3





Less then 0.5%

Loss On Ignition (LOI)

Less then 0.5%

Weather effects on Granite


Effects of Wind

Since granite is impervious to water, it does not expand and contract due to soaking up water. Instead, it expands and contracts once cracks open up on its surface, allowing water to seep in. One way in which these cracks are formed is through wind. Wind is formed due to thermal fluctuations in the atmosphere. Cold and hot winds weather granite by bombarding it with small grains of dust and dirt. It can also cause boulders to become unstable and fall, which can also create cracks. Once cracks are formed, the action of wind can further expand the cracks through the weathering process.

Effects of Rain

When rain falls, it collects in the cracks that opened up on the surface of granite. Rain water can be slightly acidic or basic, both of which can cause small reactions on the surface of the granite, which can break it down. When rain falls into cracks and crevices during the winter, it can become trapped and freeze. When rain freezes in the cracks, it expands the crack with it. Over time, this process can lead to cracks in the granite becoming larger and larger, breaking it down even further.

Effects of Heat

Large fluctuations in temperature can effect the weathering of granite. In desert environments, granite is subjected to large fluctuations between the heat of the day and the cold of the night. The heat of the day causes the rock to swell. With every 10-degree Celsius increase in temperature, there is a 2.5 times increase in the rate of a chemical reaction. When heat is coupled with water, like during a summer storm, the two factors can combine to create a stronger weathering process.

Effects of Cold

The cold causes granite to compress, or shrink, just as the heat causes it to expand. However, freezing temperatures also cause water to freeze and expand. During times of the year when rain is followed by a freeze, water trapped in cracks in the granite expand as the rock itself contracts. This causes the crack to expand and become weaker. When the weather warms, the water is heated as it melts, causing further chemical reactions to occur. The cycle of hot and cold, coupled with other meteorological factors such as rain and wind, is a part of the how granite is broken down into smaller pieces, eventually forming the rich soil in which plants thrive.

Marble Stone

What is Marble

Marble is an extremely hard, metamorphic stone composed of calcite(CaCO3).  It is formed as a result of the recrystallization of limestone under the intense pressure and heat of geologic processes.  The effect of this process is the creation of a stone with a very tight crystalline structure and small but definite porosity.  Because of its structure, marble can take a very high polish and is a very popular decorative stone for architectural and sculptural uses. It has been a symbol of beauty in the grand buildings built by emperors. Marble is used in both internal and external applications, and is available in several colors and shapes.Impurities present in the limestone during the recrystallization period affect the mineral composition of the marble which is formed. The minerals that result from impurities give marble a wide variety of colors. The color of marble ranges from the brilliant white of calcite to black, including blue-gray, red, yellow and green, depending upon the mineral composition. Marble that has limonite is yellow, and marble with serpentine is green in color. The purest calcite marble is white in color. Marble containing hematite is reddish in color. The restricted marble porosity, mainly when refined, makes it less susceptible to water damage .Marble is readily dissolved by acids, even very dilute acids .calcium carbonate, the main ingredient of marble, is exceedingly susceptible to acidic agents. it rapidly dissolves in some acids however the actual results of acidic exposure will vary with the nature of the acid.  Marble does not split easily into sheets of equal size and must be mined with care. 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. These tiles are either polished or honed. Polished tiles provide a stylish appearance, though are extremely slippery when wet. Honed tiles offer more grip and are considered safe.

Uses of Marble

Marble has always been highly valued for its beauty, strength, and resistance to fire and erosion. it is considered the stone for the emperors and gods. Marble has many decorative and structural uses. It is used for outdoor sculpture as well as for sculpture bases; in architecture it is used in exterior walls and veneers, flooring, decorative features, stairways and walkways. The ancient Iranian & Greeks were good user of marble in their buildings and statues. Carrara marbles from the Apuane Alps in Italy were subsequently exploited and today are still the most sought white marbles for statuary work .The Italian artist Michelangelo used marble from Carrara in a number of sculptures. The ancient Greeks are famed for their genius in forming statuary and basreliefs from Parian marble, one of the finest and purest white marbles ever discovered. Marble has decorated the corridors of cathedrals and historical places. Marble tiles cover the floors of the affluent and also beautifies the baths of more moderate homeowners.
Very pure calcite marble is used for most statues. They are translucent. Large blocks of colored marble are used for columns, floors, and other parts of buildings. High-grade marble graces the exteriors of many of the world’s finest buildings and, because of its high resistance to heat, it is being used increasingly in the erection of fireproof buildings, for floors, and for the overlaying of inside walls and ceilings.  Marbles are suitable for internal and external applications. However, due to modern-day environmental pollution, the polish on marble used for external applications may not be durable.
Smaller pieces of marble are crushed or finely ground and used as abrasives in soaps and other such products. Crushed or ground marble is also used in paving roads and in manufacturing roofing materials and soil treatment products. Among the many other uses of this so-called dimension marble, in addition to decorative work and monuments, are tiling, washbasins, interior window sills, vases, chimney pieces, veneer, ashlar, and electric power panels
The way in which the stone is used may be a factor in limiting or controlling the severity of exposure.  The use or function of the marble may also affect the feasibility of applying certain treatments, but type of use is not the primary factor in the major types of deterioration and damage to which marble is susceptible.

Physical Properties of Marble

Physically, these are recrystallized, Hard, Compact, fine to very fine grained metamorphosed rocks capable of taking shining polish.


3 to 4 on Moh's Scale


2.55 to 2.7 Kg/cm3

Compressive Strength

70 to 140 N/mm2

Modulus of Rupture

12 to 18 N/mm2

Water Absorption

Less than 0.5%
(except Rainforest Green/Brown with 2-3%)


Quite low

Weather Impact


Chemical Properties of Marble

Chemically, they are crystalline rocks composed predominantly of calcite, dolomite or serpentine minerals. The other minor constituents vary from origin to origin.

Lime (CaO)


Silica (SiO2)

3-30% (varies with variety)


20 to 25%

FeO + Fe2O3


Loss On Ignition (LOI)


Weather Effects On Marble

The forces of nature may produce a decaying effect on the look and structural reliability of marble. These agents include temperature, snow, rain, wind and atmospheric pollutants. Rust can only affect marble if there are some ferrous (iron-based) metals in the marble somewhere.
Chemical weathering is worse for marble because it is composed of calcite, which dissolves very easily in hydrochloric acid. Even a small amount of acid can make the marble weather quickly.Weathering agents normally act in combination with the other agents to increase the deterioration of marble. Rain water, particularly in combination with the atmospheric gases, may cause dissolution of the marble, generating salt movement within the micro-structure. Temperature can intensify the deterioration rate, and the patterns of salt relocation within the stone. High temperatures normally multiply the chemical changes. Sudden changes in temperature can cause stresses due to the differential in expansion. Moisture is considered to be one of the foremost causes of the problems that may happen. However other troubles like erosion due to wind and mutilation may also occur.

Lime stone

Lime stone