Tuzlaite | |
---|---|
General | |
Category | Borates |
Formula (repeating unit) | NaCaB5O8(OH)2 · 3H2O |
IMA symbol | Tuz |
Strunz classification | 6.EC.25 |
Crystal system | Monoclinic |
Crystal class | 2/m - Prismatic |
Space group | P21/c |
Unit cell | a = 6.506(1) b = 13.280(3) c = 11.462(3) β = 92.97(2)◦ Z=4 |
Identification | |
Color | Colorless to White |
Crystal habit | Prismatic crystals, elongated along [001] |
Cleavage | On {001}, perfect |
Mohs scale hardness | 2 - 3 |
Luster | Silky to pearly |
Streak | White |
Density | 2.23 g/cm |
Optical properties | Biaxial Positive |
Ultraviolet fluorescence | None |
References | [1] [2] [3] |
Tuzlaite is a borate mineral, associated with halides, named after the Tuzla salt mines in Bosnia and Hercegovina. A multitude of rare evaporate minerals have been discovered there, it being the only major evaporate deposit in the Balkans. [4] This mineral has been approved as tuzlaite by the International Commission on New Minerals and Mineral Names. [5]
Tuzlaite is found alongside several rare evaporates such as northupite, searlesite, and bradleyite. Between the layers of salt, there are approximately 50m thick layers of grey to black dolomitic marls that occasionally get cut by white veinlets composed of the mineral tuzlaite. [6] These veinlets can be surrounded by a coronitic halite phase that can be dissolved off with H2O, leaving us with colorless to white crystals of tuzlaite up to 0.5mm in length. Most of these crystals can be intergrown, but some are suitable for X-ray single-crystal structure analysis. [4]
Tuzlaite ranges from white to colorless with a perfect cleavage parallel to {001}. The hardness of the mineral is within the range of 2 to 3 on the Mohs Hardness scale. The lustre of Tuzlaite is silky to pearly and is reliant on its growing conditions and the size of the crystal with no reaction to short-wave and long-wave UV light. Tuzalite decomposes in hydrochloric acid leaving a transparent solution with no residue, but does not react with H2O. [4]
Tuzlaite has refractive indices nx = 1.532(2), ny = 1.544(2), and nz = 1.561(2). The optical orientation is Y = b, Z:a = 14° (in acute angle β ). It is optically positive with Δ = 0.029(l), measured with a compensator and calculated from refractive indices. The optic axial angle was measured as 2Vz = 82(1)°; 2Vz = 80.9° was calculated from refractive indices. Indicatrix dispersion wasn't observed. [4]
(1) | (2) | |
B2O3 | 52.19 | 52.24 |
Al2O3 | 0.26 | - |
CaO | 14.64 | 16.83 |
SrO | 0.21 | - |
Na2O | 10.25 | 9.30 |
H2O | 21.66 | 21.63 |
Total | 99.21 | 100.00 |
(1) Tuzla mine in Bosnia-Herzegovina; average of six analyses by flamephotometry, TGA, and crystal-structure analysis; corresponds to Na1.00(Ca0.87Na0.10Sr0.01)Σ=0.98B4.98Al0.02 O7.92(OH)2 • 3H2O. [6]
(2) NaCaB5O8(OH)2 • 3H2O. [6]
All atoms in the structure for tuzlaite were refined and located. Tuzlaite has a pentaborate sheet structure with layers parallel to (001). These sheets are connected by Ca and Na coordinated with three H2O molecules, where Ca is eightfold coordinated by six borate O atoms and two H2O molecules. Na is sevenfold coordinated by four borate O atoms and three H2O molecules. Na and Ca polyhedra form continuous chains with a Ca-Ca-Na-Na-Ca-Ca sequence. Face sharing occurs between Ca and Na polyhedra. Na and Ca polyhedral chains penetrate the ten-membered borate rings excentrically; thus the remaining space is filled by H2O molecules, which are linked by H bonds to the borate sheet. [4]
A borate is any of a range of boron oxyanions, anions containing boron and oxygen, such as orthoborate BO3−3, metaborate BO−2, or tetraborate B4O2−7; or any salt of such anions, such as sodium metaborate, Na+[BO2]− and borax (Na+)2[B4O7]2−. The name also refers to esters of such anions, such as trimethyl borate B(OCH3)3.
Ulexite (NaCaB5O6(OH)6·5H2O, hydrated sodium calcium borate hydroxide), sometimes known as TV rock or television stone due to its unusual optical characteristics, is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. Ulexite was named for the German chemist Georg Ludwig Ulex (1811–1883) who first discovered it.
Vivianite (Fe2+
3(PO
4)
2·8H
2O) is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg2+, and calcium Ca2+ may substitute for iron Fe2+ in the structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals.
Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone.
Scolecite is a tectosilicate mineral belonging to the zeolite group; it is a hydrated calcium silicate, CaAl2Si3O10·3H2O. Only minor amounts of sodium and traces of potassium substitute for calcium. There is an absence of barium, strontium, iron and magnesium. Scolecite is isostructural (having the same structure) with the sodium-calcium zeolite mesolite and the sodium zeolite natrolite, but it does not form a continuous chemical series with either of them. It was described in 1813, and named from the Greek word, σκώληξ (sko-lecks) = "worm" because of its reaction to the blowpipe flame.
The Borate Minerals are minerals which contain a borate anion group. The borate (BO3) units may be polymerised similar to the SiO4 unit of the silicate mineral class. This results in B2O5, B3O6, B2O4 anions as well as more complex structures which include hydroxide or halogen anions. The [B(O,OH)4]− anion exists as well.
Carnallite (also carnalite) is an evaporite mineral, a hydrated potassium magnesium chloride with formula KCl.MgCl2·6(H2O). It is variably colored yellow to white, reddish, and sometimes colorless or blue. It is usually massive to fibrous with rare pseudohexagonal orthorhombic crystals. The mineral is deliquescent (absorbs moisture from the surrounding air) and specimens must be stored in an airtight container.
Microlite was once known as a pale-yellow, reddish-brown, or black isometric mineral composed of sodium calcium tantalum oxide with a small amount of fluorine. Its chemical formula is(Na,Ca)2Ta2O6(O,OH,F). Today it is a name of a group of oxide minerals of a similar stoichiometry having tantalum prevailing over titanium and niobium. The microlite group belongs to a large pyrochlore supergroup that occurs in pegmatites and constitutes an ore of tantalum. It has a Mohs hardness of 5.5 and a variable specific gravity of 4.2 to 6.4. It occurs as disseminated microscopic subtranslucent to opaque octahedral crystals with a refractive index of 2.0 to 2.2. Microlite is also called djalmaite, but both names are now obsolete.
Jarosewichite is a rare manganese arsenate mineral with formula: Mn2+3Mn3+(AsO4)(OH)6. It was first described in Franklin, New Jersey which is its only reported occurrence. Its chemical composition and structure are similar to chlorophoenicite. This mineral is orthorhombic with 2/m2/m2/m point group. Its crystals are prismatic or barrel-shaped. The color of jarosewichite is dark red to black. It has subvitreous luster of fracture surfaces and reddish-orange streak. This mineral occurs with flinkite, franklinite, andradite and cahnite.
Sborgite is a sodium borate mineral with formula Na[B5O6(OH)4]·3H2O. The formula can be written as the oxide formulation, Na2O.5B2O3.10H2O. Sometimes called sodium pentaborate pentahydrate it contains the pentaborate anion, (B5O6(OH)4)−.
Yuksporite is a rare inosilicate mineral with double width, unbranched chains, and the complicated chemical formula K4(Ca,Na)14Sr2Mn(Ti,Nb)4(O,OH)4(Si6O17)2(Si2O7)3(H2O,OH)3. It contains the relatively rare elements strontium, titanium and niobium, as well as the commoner metallic elements potassium, calcium, sodium and manganese. As with all silicates, it contains groups of linked silicon and oxygen atoms, as well as some associated water molecules.
Barbertonite is a magnesium chromium carbonate mineral with formula of Mg6Cr2(OH)16CO3·4H2O. It is polymorphous with the mineral stichtite and, along with stichtite, is an alteration product of chromite in serpentinite. Barbertonite has a close association with stichtite, chromite, and antigorite (Taylor, 1973). Mills et al. (2011) presented evidence that barbertonite is a polytype of stichtite and should be discredited as a mineral species.
Nambulite is a lithium bearing manganese silicate mineral with the chemical formula (Li,Na)Mn4Si5O14(OH). It is named after the mineralogist, Matsuo Nambu (born 1917) of Tohoko University, Japan, who is known for his research in manganese minerals. The mineral was first discovered in the Funakozawa Mine of northeastern Japan, a metasedimentary manganese ore.
Studenitsite is a rare borate mineral with chemical formula of NaCa2[B9O14(OH)4]·2H2O.
Pimelite was discredited as a mineral species by the International Mineralogical Association (IMA) in 2006, in an article which suggests that "pimelite" specimens are probably willemseite, or kerolite. This was a mass discreditation, and not based on any re-examination of the type material. Nevertheless, a considerable number of papers have been written, verifying that pimelite is a nickel-dominant smectite. It is always possible to redefine a mineral wrongly discredited.
Carlosruizite is a sulfate or selenate–iodate mineral with chemical formula: K6(Na,K)4Na6Mg10(SeO4)12(IO3)12·12H2O. It has a low density (specific gravity of 3.36), colorless to pale yellow, transparent mineral which crystallizes in the trigonal crystal system. It forms a series with fuenzalidaite.
Ruizite is a sorosilicate mineral with formula Ca2Mn2Si4O11(OH)4·2H2O. It was discovered at the Christmas mine in Christmas, Arizona, and described in 1977. The mineral is named for discoverer Joe Ana Ruiz.
Junitoite is a mineral with formula CaZn2Si2O7·H2O. It was discovered at the Christmas mine in Christmas, Arizona, and described in 1976. The mineral is named for mineral chemist Jun Ito (1926–1978).
Köttigite is a rare hydrated zinc arsenate which was discovered in 1849 and named by James Dwight Dana in 1850 in honour of Otto Friedrich Köttig (1824–1892), a German chemist from Schneeberg, Saxony, who made the first chemical analysis of the mineral. It has the formula Zn3(AsO4)2·8H2O and it is a dimorph of metaköttigite, which means that the two minerals have the same formula, but a different structure: köttigite is monoclinic and metaköttigite is triclinic. There are several minerals with similar formulae but with other cations in place of the zinc. Iron forms parasymplesite Fe2+3(AsO4)2·8H2O; cobalt forms the distinctively coloured pinkish purple mineral erythrite Co3(AsO4)2·8H2O and nickel forms annabergite Ni3(AsO4)2·8H2O. Köttigite forms series with all three of these minerals and they are all members of the vivianite group.
Serpierite (Ca(Cu,Zn)4(SO4)2(OH)6·3H2O) is a rare, sky-blue coloured hydrated sulfate mineral, often found as a post-mining product. It is a member of the devilline group, which has members aldridgeite (Cd,Ca)(Cu,Zn)4(SO4)2(OH)6·3H2O, campigliaite Cu4Mn2+(SO4)2(OH)6·4H2O, devilline CaCu4(SO4)2(OH)6·3H2O, kobyashevite Cu5(SO4)2(OH)6·4H2O, lautenthalite PbCu4(SO4)2(OH)6·3H2O and an unnamed dimorph of devilline. It is the calcium analogue of aldridgeite and it is dimorphous with orthoserpierite CaCu4(SO4)2(OH)6·3H2O.
Lemanskiite is a mineral that was first discovered in a mine at Abundancia mine, El Guanaco mining district, Chile, with the ideal formula of NaCaCu5(AsO4)4Cl·3H2O. Originally, this mineral was discovered as being dimorphus with lavendulan, but in 2018 it was revised to only have 3 water molecules. Lemanskiite typically occurs as rosette-shaped aggregates of thin lamellar or needle-shaped aggregates, such as lammerite. Lemanskiite is dark sky blue with a light blue streak, it is brittle with an excellent cleavage plane. It was found on a dumping site in the abandoned Abundancia mine, El Guanaco mining district, Region II, Antofagasta Province, Chile The new mineral has been named after Chester S. Lemanski, Jr. This mineral and name were then approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association.