Baryte

Baryte (BaSO₄) is a mineral consisting of barium sulfate. It is generally white or colorless, and is the main source of barium. Barite is the unofficial American spelling. The mineral is also called heavy spar or tiff. The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among alchemists for the phosphorescent specimens found in the 1600s near Bologna by Vincenzo Cascariolo. Its Mohs hardness is 3, the refractive index is 1.63 and it has a specific gravity of 4.3-5. Its crystal structure is orthorhombic.

Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore. It is often associated with the minerals anglesite and celestine.

The name baryte is derived from the Greek word βαρύς (heavy). In commerce, the mineral is sometimes referred to as “barytes.” When the International Mineralogical Association formed in 1959 the American spelling “barite” was chosen as the official over the older “baryte”. This decision was reversed in 1978. The term “primary baryte” refers to the first marketable product, which includes crude baryte (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation, and magnetic separation. Most crude baryte requires some upgrading to minimum purity or density. Baryte that is used as an aggregate in a “heavy” cement is crushed and screened to a uniform size. Most baryte is ground to a small, uniform size before it is used as a filler or extender, an addition to industrial products, or a weighting agent in petroleum well drilling mud.

Large barite crystals from Nevada, USA

Some 77% worldwide is used as a weighting agent for drilling fluids in oil and gas exploration. Other uses are in added-value applications which include the car, electronics, TV screen, rubber, and glass ceramics and paint industry, radiation shielding and medical applications (barium meals). Baryte is supplied in a variety of forms and the price depends on the amount of processing; filler applications commanding higher prices following intense physical processing by grinding and micronising, and there are further premiums for whiteness and brightness and colour.

Baryte is used in the manufacture of paints and paper. Although baryte contains a “heavy” metal (barium), it is not considered to be a toxic chemical by most governments because of its extreme insolubility.

Ore

An ore is a type of rock that contains minerals such as gemstones and metals that can be extracted through mining and refined for use. Samples of ore in the form of exceptionally beautiful crystals, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or crystalline formations of metals such as gold or copper may command a value far beyond their value as mere ore or raw metal for subsequent reduction to utilitarian purposes.

 

The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighted against the contained metal value of the rock to determine what ore can be profitably extracted and what ore is of too low a grade to be worth mining. Metal ores are generally oxides, sulfides, silicates, or “native” metals (such as native copper) that are not commonly concentrated in the Earth’s crust or “noble” metals (not usually forming compounds) such as gold. The ores must be processed to extract the metals of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological processes. The process of ore formation is called ore genesis.

from wikipedia

Marble

Marble is a nonfoliated 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. The word “marble” is colloquially used to refer to many other stones that are capable of taking a high polish.

Marble is a metamorphic rock resulting from regional or rarely contact metamorphism of sedimentary carbonate rocks, either limestone or dolomite rock, or metamorphism of older marble. This metamorphic process causes a complete recrystallization of the original rock into an interlocking mosaic of calcite, aragonite and/or dolomite crystals. The temperatures and pressures necessary to form marble usually destroy any fossils and sedimentary textures present in the original rock.

 

Pure white marble is the result of metamorphism of very pure limestones. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally high magnesium limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.

from wikipedia

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tors, and rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels.

Granite is nearly always massive (lacking internal structures), hard and tough, and therefore it has gained widespread use as a construction stone. The average density of granite is 2.75 g/cm3 and its viscosity at standard temperature and pressure is ~4.5 * 10^19 Pa·s  . The word granite comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.

Granite is currently known only on Earth where it forms a major part of continental crust. Granite often occurs as relatively small, less than 100 km2 stock masses (stocks) and in batholiths that are often associated with orogenic mountain ranges. Small dikes of granitic composition called aplites are often associated with the margins of granitic intrusions. In some locations very coarse-grained pegmatite masses occur with granite.

Granite has been intruded into the crust of the Earth during all geologic periods, although much of it is of Precambrian age. Granitic rock is widely distributed throughout the continental crust of the Earth and is the most abundant basement rock that underlies the relatively thin sedimentary veneer of the continents.

Despite being fairly common throughout the world, certain areas are well known for their commercial granite quarries:
from wikipedia

Limestone

Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3).

Limestone often contains variable amounts of silica in the form of chert and/or flint, as well as varying amounts of clay, silt and sand as disseminations, nodules, or layers within the rock. The primary source of the calcite in limestone is most commonly marine organisms. These organisms secrete shells that settle out of the water column and are deposited on ocean floors as pelagic ooze or alternatively are conglomerated in a coral reef (see lysocline for information on calcite dissolution). Secondary calcite may also be deposited by supersaturated meteoric waters (groundwater that precipitates the material in caves). This produces speleothems such as stalagmites and stalactites. Another form taken by calcite is that of oolites (oolitic limestone) which can be recognized by its wwe Limestone makes up about 10% of the total volume of all sedimentary rocks. Limestones may also form in both lacustrine and evaporite depositional environments.

from wikipedia

Pebble

A pebble is a clast of rock with a particle size of 4 to 64 millimeters based on the Krumbein phi scale of sedimentology. It is generally considered to be larger than gravel and smaller than cobble. A rock made predominantly of pebbles is termed a conglomerate. Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history.

A beach composed chiefly of surface pebbles is commonly termed a shingle beach. This type of beach has armoring characteristics with respect to wave erosion, as well as unusual ecological niches which can provide habitat for a number of rare and endangered species.

Pebbles come in a variety of different colors and textures, and can often have streaks of quartz and different colored sedimentary rock. Pebbles are mostly smooth but, dependent on how frequently they come in contact with the sea, they can have marks of contact with other rocks or pebbles. Pebbles left above the high water mark, may have the growth of organisms such as lichen on them, signifying the lack of contact with sea water.

Pebbles can also be found inland where ancient seas used to be cover the land, when seas retreat the rocks become landlocked. Pebbles can also form in rivers, and travel into estuaries where the smoothing continues in the sea.