Mineral Brookite

The chemical composition of mineral Brookite is indicated by the formula TiO2, a Titanium Oxide. This Brookite belongs to the Oxides and Hydroxides mineral class. The Oxides mineral class, of course with the inclusion of the Hydroxides, is considered as a rather diverse class. This class usually includes corundum or minerals that are appear quite hard. Those minerals that are quite soft like psilomelane are also included in this Oxides and Hydroxides mineral class. Some gemstones such as spinel, chrysoberyl and corundum and some other metallic minerals like hematite also belong in this mineral class. Many Oxides and Hydroxides minerals appear black but some can be found in a very colorful appearance. It has been considered that the large diversity of the Oxides and Hydroxides mineral class can be partially attributed to the great abundance of the oxygen, which can be found in the crust layer of the Earth. It has been found that oxygen comprises almost over 45% of the crust layer of the Earth by weight. Most oxygen is chemically found locked up in some other more complex minerals based on their chemical complex ions like PO4, BO3, NO3, CO3, SO4, SiO4 and many others. But a single oxygen ion has many opportunities to combine with various elements in many different ways. In a strict sense they say, those minerals that belong to the more complex mineral classes like the silicates are really Oxides. But mineralogists made Oxides and Hydroxides mineral class to comprise all non-complex minerals containing oxygen or hydroxide. This is so because it would be cumbersome for them to be able to deal with only four different mineral classes such as the elemental class, the sulfides class, the halides class and the extremely diverse mineral class, the Oxides and Hydroxides together with its many subclasses and comprising almost 90% of all minerals. This Oxides and Hydroxides mineral class comprises minerals containing mostly ionic bonds and this is considered as a helpful distinguishing factor for its members because most complex minerals of other classes contain typical covalent bonds in nature. Take Quartz for instance, its chemical composition is indicated by the formula SiO2. Quartz would be considered an Oxide but because of its covalent silicon oxygen bonds it was classified to belong in the silicates mineral class, in a tectosilicates group to be specific. The positive one (+1) state of hydrogen is considered as a single proton and is so small that when combined with oxygen it would disappear into the oxygen and results to the OH group, which is almost of the same size as a single oxygen ion with negative two (-2) charge. The OH group can actually fit into many crystal sites in which oxygen would otherwise occupy, but only with a negative one (-1) charge. Adding negative charges or fewer positive charges can do the balancing of the crystal.

Brookite minerals are considered as very minor ores of titanium and also as mineral specimens. Brookite ore minerals are usually found exhibiting nice and interesting microscope views under an ore polarizing light microscope. Brookite is known to be a polymorph mineral with two other interesting minerals namely rutile and anatase. These three minerals have different structures but they actually share the same chemistry. Brookite is usually found reverting to rutile mineral at higher temperature of about 750º Celsius. This Rutile mineral is a most well known and most common mineral of the three. Brookite and rutile minerals are known to share many of the same properties such as luster and color. Some other properties such as density and hardness are actually nearly the same. Due to their structural differences, rutile and Brookite are found having different cleavage types and crystal habits.

Brookite mineral was first discovered in the year 1825 at Wales in England. Brookite mineral species was named after Henry James Brucke (1771-1857), a known London mineralogist and also a wool trader. . Brookite mineral are commonly associated with several other interesting minerals such as rutile, feldspars, anatase, sphene, chalcopyrite, hematite and quartz.

Brookite mineral specimens are commonly found in shades of dark brown to greenish black in reflected light of petrographic polarizing light microscopes. The luster that is commonly exhibited by Brookite when it is viewed in reflected light of geological microscope is usually a variation of adamantine to submetallic. The cleavage of Brookite is commonly found as poor prismatic and is usually found in the basal direction when evaluated between crossed nicols of polarizing light microscope for geologists. It is also commonly found having a subconchoidal to uneven fracture under several adjustments on the aperture diaphragm of the petrographic polarizing light microscope. The fractures are usually developed in brittle materials that are commonly characterized by semi-curving surfaces, which are seen clearly with the aid of geological polarizing light microscopes. Fracture describes how a mineral breaks when broken contrary to its natural cleavage planes. The hardness measure of mineral Brookite using the Mohs scale method is commonly found ranging from 5.5 to 6. When specimens of mineral Brookite are rubbed on a white porcelain streak plate, they are usually found leaving a light brown to white streak. The specific gravity measure of Brookite is commonly found ranging from 3.9g/cm³ to 4.1g/cm³, which is considered average for metallic minerals.

Brookite minerals are known to crystallize in the orthorhombic system, which can be seen clearly with the aid of a geological microscope. This crystal system comprises crystals having three mutually perpendicular axes, of which all are of different lengths. Brookite mineral crystals are commonly found opaque in appearance. The crystal habit of mineral Brookite usually include the typical tabular to platy crystals with a pseudohexagonal outline, which is clearly visible under a geological microscope. They can be also found in platy or sheets forms. They can be also found in tabular forms, which are usually in dimensions that are thin in one direction. They may also appear in shape like a book. The specimens of Brookite, which are found in Magnet Cove, Arkansas, are usually found having crystals, which are more equant with more complex facets that are usually found exhibiting a nice and splendid microscope images under a polarized light microscope

Brookite minerals are found biaxial positive figures between crossed nicols of geological polarizing light microscope. It is commonly found having relatively strong dispersion and commonly with crossed axial dispersion in transmitted light of petrographic polarizing light microscope. Brookite is commonly found as a non-radioactive mineral after several chemical evaluations. Brookite mineral crystals are actually brittle, a property that is commonly displayed by glasses and most non-metallic minerals. Uncertain twins can be found when mineral specimen Brookite is evaluated under a geological polarizing microscope. It also displays a very high surface relief when it is examined with the aid of a polarizing light microscope for geologists. It also exhibits a weak pleochroism under polarized light microscopes. There is no specific data on the toxicity and health dangers of mineral Brookite. However, mineral specimens of Brookite should be treated with great care and use of sensible precaution is advised upon handling them.

Brookite minerals are considered as accessory minerals in alpine veins in gneiss and schist. They can be also found in placer deposits and they less commonly form in zones of contact metamorphism. They also form in hydrothermal veinlets. Brookite is considered as a common detrital mineral. The best field indicators of Brookite minerals usually include streak, luster, locality, density, crystal habit and its wonderful association with several other interesting minerals. Brookite minerals notably occur at some types of localities including some areas in the United States like Arkansas, New York, Montana and Massachusetts as well as localities like Russia, Austria, Switzerland and England.