Doyleite is a rare aluminum trihydroxide

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

named in honor of its discoverer, the Canadian physician Earl Joseph (Jess) Doyle. It was first definitively described in 1985 (although a partial description was published in 1979) and it is approved by the IMA. It was described from

Mont Saint-Hilaire Mont Saint-Hilaire (English: Mount Saint-Hilaire; abe, Wigwômadenizibo; see for other names) is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the ...

, where it is extremely rare.

Properties

Doyleite grows in small square tabular crystals, which form rosettes. Individual crystals can grow up to 8 mm. The mineral has a layered micaceous structure. This pinacoidal mineral mostly consists of oxygen (61.53%) and aluminum (34.59%), but also contains hydrogen (3.88%). Doyleite does not display any radioactive properties. At room temperature, doyleite is not soluble in a 1:1 ratio of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...

, and

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

. Crystals are tabular on (010), which show forms of , , and . Occasionally, however, it shows forms of and . Some specimens are coated with a thin film of dark brown amorphous material, thought to be iron oxide. The mineral has been determined to be

triclinic 180px, Triclinic (a ≠ b ≠ c and α ≠ β ≠ γ ) In crystallography, the triclinic (or anorthic) crystal system is one of the 7 crystal systems. A crystal system is described by three basis vectors. In the triclinic system, the crystal is ...

by a three-dimensional single-crystal diffraction study. It has a bilayer structure, similar to its polymorphs. There is good correspondence between the AFM images of doyleite's (010) surface and the calculated structure. The hydroxyl group's intra-layer interactions show no

Raman scattering Raman scattering or the Raman effect () is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a ...

in contrast to its polymorphs. The P1 j structure model is slightly more unstable than the non-centrosymmetrical P1 structure model. The layered structures are similar to those found in one of its polymorphs, bayerite. The difference is within the interlayer shift vectors only. Doyleite is the least stable of the polymorphs.

Mining and environment

Doyleite is associated with

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs sca ...

zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the r ...

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

albite Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. I ...

siderite Siderite is a mineral composed of iron(II) carbonate (FeCO3). It takes its name from the Greek word σίδηρος ''sideros,'' "iron". It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Zinc, magnesium and ...

and

molybdenite Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum ato ...

. It is the polymorph of

gibbsite Gibbsite, Al(OH)3, is one of the mineral forms of aluminium hydroxide. It is often designated as γ-Al(OH)3 (but sometimes as α-Al(OH)3.). It is also sometimes called hydrargillite (or hydrargyllite). Gibbsite is an important ore of aluminiu ...

, nordstrandite, bayerite and UM1990-28-OHF:Al. Doyleite has two type localities, one is the Poudrette and Francon quarry, Canada; the other is Mont Saint-Hilaire, also in Canada. It is a late-stage hydrothermal mineral, and can form

hydrothermal mineral deposit Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth's crust through fractures. They eventually create metallic-rich fluids concentrated in a selected volume of rock, which become s ...

s. Doyleite is found lining

vug A vug, vugh, or vugg ( ) is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity (folding and faulting) are partially filled by quartz, ...

s in

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

s in

nepheline syenite Nepheline syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are al ...

. It also occurs 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 pyrite in albitite veins.{{Cite journal, last1=George, first1=Y. Chao, last2=Judith, first2=Baker, last3=Ann, first3=P. Sabina, last4=Andrew, first4=C. Roberts, date=1985, title=Doyleite, a new polymorph of Al(OH)₃, and its relationship to bayerite, gibbsite and nordstrandite, journal=Canadian Mineralogist, language=English, volume=23, pages=21–28

References

Minerals Minerals in space group 1 Aluminium minerals