Brushite is a
phosphate mineral
Phosphate minerals contain the tetrahedrally coordinated phosphate (PO43−) anion along sometimes with arsenate (AsO43−) and vanadate (VO43−) substitutions, and chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions that also fit i ...
with the chemical formula . Crystals of the pure compound belong to the monoclinic
space group
In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...
C2/c and are colorless.
[Brishite]
Webmineral It is the phosphate analogue of the arsenate
The arsenate ion is .
An arsenate (compound) is any compound that contains this ion. Arsenates are salts or esters of arsenic acid.
The arsenic atom in arsenate has a valency of 5 and is also known as pentavalent arsenic or As(V).
Arsenate resem ...
pharmacolite
Pharmacolite is an uncommon calcium arsenate mineral with formula CaHAsO4·2(H2O). It occurs as soft, white clusters of fibrous crystals and encrustations which crystallize in the monoclinic system. It is the arsenate analogue of the sulfate gypsum ...
.
Discovery and occurrence
Brushite was first described in 1865 for an occurrence on Aves Island, Nueva Esparta
The Nueva Esparta State (in Spanish: ''Estado Nueva Esparta'', ), is one of the 23 states of Venezuela. It comprises Margarita Island, Coche, and the largely uninhabited Cubagua.
The state has the smallest area, and is located off the northe ...
, Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
, and named for the American mineralogist George Jarvis Brush
George Jarvis Brush (December 15, 1831 – February 5, 1912) was an American mineralogist and academic administrator who spent most of his career at Yale University in the Sheffield Scientific School.
Career
Brush was born in Brooklyn, New York o ...
(1831–1912).[ It is believed to be a precursor of ]apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...
and is found in guano
Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...
-rich caves, formed by the interaction of guano with calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
and clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...
at a low pH. It occurs in phosphorite deposits and forms encrustations on old bones. It may result from runoff of fields which have received heavy fertilizer applications.[ Associated minerals include tanarakite, ardealite, ]hydroxylapatite
Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. ...
, variscite
Variscite is a hydrated aluminium phosphate mineral (). It is a relatively rare phosphate mineral. It is sometimes confused with turquoise; however, variscite is usually greener in color. The green color results from the presence of small amounts ...
and gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
.[
Brushite is the original precipitating material in ]calcium phosphate
The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white ...
kidney stones
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
. It is also one of the minerals present in dental calculi.
References
{{Phosphate-mineral-stub
Calcium minerals
Phosphate minerals
Cave minerals
Monoclinic minerals
Minerals in space group 9