Mineral Bytownite

The chemical composition of mineral Bytownite is indicated by the formula CaNa(Al,Si)AlSi2O8, a Calcium Sodium Aluminum Silicate. This Bytownite belongs to the Silicates mineral class. The Silicates is considered as the largest and the most complicated class of minerals. They are also the most interesting mineral class comprising wonderful and attractive mineral specimens, which are exhibiting splendid views on both transmitted and reflected light microscopes. Some geologists made an estimation that about 90% of the Earth’s crust is actually made up of silicates. It has been known also that approximately 30% of all minerals are silicates. It is not surprising to know that silicate occurs in great abundance since oxygen and silicon are popularly known as the two most abundant elements in the Earth’s crust. Silicates have the basic chemical unit of SiO4 tetrahedron shaped anionic group with a negative four charge. In the chemical structure of Silicate, it can be found that the central silicon ion has a positive four charge while every oxygen has a negative two charge. Thus, each silicon-oxygen bond in the chemical structure is equal to one half of the total bond energy of oxygen. This chemical structure condition of silicates leaves the oxygen with the option of bonding to another silicon ion and therefore linking one SiO4 tetrahedron continuously from one to another. Silicates actually possess a complicated chemical structure formed by silicate tetrahedron, which is considerably and truly amazing. They can be found forming as single units, double units, sheets, chains, rings and framework structures. These different ways of combinations that produce different types of structure formations actually makes the Silicates class the largest, the most complicated and the most interesting mineral class.

Bytownite mineral is a member of the plagioclase series but is considerably rare in occurrence. The plagioclase series is actually found comprising minerals with chemical composition ranging from pure Albite with formula NaAlSi3O8, to pure Anorthite with formula CaAl2Si2O8. By definition, Bytownite mineral must contain 30 to 10 percent sodium to 70 to 90 percent calcium in the Sodium/Calcium position in the crystal structure. The identification of various plagioclase feldspars from each other is done by gradations in their density and index of refraction in the absence of chemical analysis and/or optical measurements. The Albite type of twinning, which is commonly shown by all plagioclase feldspars, is actually named after albite. The Albite Law of twinning commonly produces twinned layers that are fractions of millimeters to several millimeters thick. These twinned layers that are produced can be actually seen as striations, which are like grooves on the surface of the crystal that can be seen clearly visible under petrographic polarizing reflected light microscopes. And unlike true striations, they can be also found appearing on the cleavage surfaces of the mineral crystals. The Carlsbad Law of twins on the other hand is found producing those crystals, which appears to be intergrown that are actually found growing in opposite directions as clearly exhibited under a geological microscope. The other two different Law of Twins, the Manebach and Baveno laws are actually found producing crystals, which are found having one prominent mirror plane and penetrant angles or notches into the crystal. Although twinned crystals are common, twin fanciers are often found collecting single crystals that are displaying a perfect twin even though they are considerably rare.

Bytownite mineral species actually derived its name from its famous locality, the Bytown, which is now called Ottawa, Ontario, Canada. The name was actually given by T. Thomson in the year 1835. Afterwards, the name Bytownite was applied by G. Tschermak to all those plagioclase feldspars that lie between labradorite and anorthite. And generally, most petrologists have adopted this. Bytownite minerals are commonly found in shades that are usually white, gray or sometimes colorless under petrographic polarizing reflected light microscopes. But this mineral can be also found in pale shades of other colors. Bytownite minerals commonly exhibit vitreous luster in reflected light of polarizing microscopes for geologist, but they may appear dull if weathered. The cleavage found when Bytownite mineral specimen is evaluated under a geological polarizing light microscope is actually perfect in one direction and good in another direction that are forming nearly right angled prisms. The fracture that is found exhibited by the mineral is commonly conchoidal when it is examined under a polarized light microscope for geologists. They can be also found having uneven or flat surfaces that are fractured in an uneven pattern. The hardness measure for mineral specimen Bytownite using the Mohs scale method is commonly found ranging from 6 to 6.5. When Bytownite mineral specimens are rubbed on the white porcelain streak plate, they are commonly found leaving a white streak. The specific gravity measure of mineral Bytownite commonly gives an approximate value ranging from 2.74g/cm³ to 2.76g/cm³, which is considered as an average value.

Bytownite mineral crystals are known to crystallize in the triclinic, which can be seen clearly with the aid of geological polarizing light microscope. This crystal system commonly comprises crystals having three axes, of which all are unequal in length and are positioned oblique to one another. Bytownite mineral crystals are commonly found translucent to opaque in appearance and only sometimes found as transparent. They are commonly found translucent in thin edges. The crystal habits of Bytownite mineral commonly include blocky or tabular crystals, which are clearly visible with the aid of a polarizing light microscope for geologists. The tabular crystals are commonly forming dimensions that are shaped like a book. They are rarely found as free crystals but they actually have a nearly rectangular or square cross that are terminated by a slanted dome and pinacoid faces. They are commonly found having twinned crystals as clearly exhibited under a polarizing light microscope. Bytownite minerals are also usually found as grains in gabbros and also in compact masses. They can be also found in coarse crystalline dimensions that commonly occur as well-formed coarse sized crystals. Sometimes they are also found in granular forms and they generally occur as anhedral to subhedral crystals in matrix, which are splendidly exhibited under a polarized light microscope. Striated crystals can be also found visible and this are seen as parallel lines in the crystal surfaces or cleavage face when the mineral specimen is evaluated with the aid of a petrographic polarizing light microscope. Bytownite minerals are commonly associated with other interesting and splendid minerals such as biotite, pyroxenes and hornblende.

When Bytownite mineral specimens are evaluated between crossed nicols of the petrographic polarizing light microscope, they can be actually found having an index of refraction ranging from 1.565 to 1.585. Bytownite can be also found having a lamellar twinning. This may actually cause a grooved effect on the Bytownite crystals and the cleavage surfaces of this mineral, which may appear as striations. Bytownite minerals are also non-fluorescent minerals in either short or long wave ultraviolet light. Bytownite mineral specimen is found to be a biaxial figure under a petrographic polarizing microscope. Bytownite mineral is both an optically positive and an optically negative figure. Bytownite minerals are also found having a low surface relief when specimens of this mineral are evaluated between crossed nicols of petrographic polarizing light microscope. They also display a strong dispersion in transmitted light of geological microscopes. After several chemical evaluations, Bytownite is found to be non-radioactive. There is no specific data on the toxicity and health dangers for mineral Bytownite. However, Bytownite mineral specimens should be treated with great care and use of sensible precaution is advised upon handling them.

Bytownite minerals are commonly formed in magmatic and metamorphic rocks. They can be also found occurring in basic igneous rocks and in stony meteorites. The best field indicators of mineral Bytownite usually include density, twinning striations, index of refraction and occurrence. Bytownite minerals are actually notably found at some limited localities such as South Africa, Scotland and the Ottawa, Canada that is formerly called as Bytown.