Valentinite

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Valentinite
Valentinite-205948.jpg
A sample of valentinite from Algeria (size: 6.9 x 4.4 x 3.3 cm)
General
Category Oxide minerals
Formula
(repeating unit)
Sb2O3
IMA symbol Vln [1]
Strunz classification 4.CB.55
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pccn
Unit cell a = 4.91  Å, b = 12.46 Å
c = 5.42 Å; Z = 4
Identification
ColorColorless, snow-white, pale yellow, pink, gray to brownish
Crystal habit Prismatic crystals, sometimes flattened, fan-shaped or stellate aggregates of crystals; lamellar, columnar, granular, massive.
Cleavage {110}, perfect; {010}, imperfect
Tenacity Brittle
Mohs scale hardness2.5–3
Luster Adamantine, pearly on cleavages
Streak White
Diaphaneity Transparent to translucent
Specific gravity 5.76
Optical propertiesBiaxial (−)
Refractive index nα = 2.180 nβ = 2.350 nγ = 2.350
Birefringence δ = 0.170
2V angle Very small
References [2] [3] [4]

Valentinite is an antimony oxide mineral with formula Sb 2 O 3. Valentinite crystallizes in the orthorhombic system and typically forms as radiating clusters of euhedral crystals or as fibrous masses. It is colorless to white with occasional shades or tints of yellow and red. It has a Mohs hardness of 2.5 to 3 and a specific gravity of 5.76. [5] Valentinite occurs as a weathering product of stibnite and other antimony minerals. It is dimorphous with the isometric antimony oxide senarmontite. [2]

Contents

Historical data

Valentinite is a mineral named in the middle of the 19th century in honour of Basilius Valentinus, a writer on alchemy. He is the supposed author of the first book to give a detailed description of antimony and its compounds. From the contents of the book it is also obvious that Valentinus was familiar with the synthetic preparation of antimony trioxide, which was called 'the antimony flower'.[ citation needed ]

Valentinite was first described in 1845 for an occurrence in the Les Chalanches Mine, Allemond, Isère, Auvergne-Rhône-Alpes, France. [3] The first description of its occurrence in the region of Příbram in Bohemia comes roughly from the same time. This particular locality at one time produced the very best crystals of this mineral. The largest crystals found there measured up to 3 cm. Grouped in rich druses, they developed in vein cavities with galena.

Occurrence

Valentinite from Djebel Nador, Constantine Province, Algeria Valentinite-155153.jpg
Valentinite from Djebel Nador, Constantine Province, Algeria

Valentinite is a weathering product of hydrothermal antimony-bearing veins, where it forms as a secondary mineral through oxidation in the upper parts of the deposits. It occurs associated with stibnite, native antimony, stibiconite, cervantite, kermesite and tetrahedrite. [2]

A rich deposit of valentinite has been found in the Constantine province of Algeria. This is the only deposit where it is mined as an ore, with 83% antimony.[ citation needed ] In all other locations it occurs in negligible quantities.

See also

Related Research Articles

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<span class="mw-page-title-main">Stibnite</span> Sulfide mineral

Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metalloid antimony. The name is derived from the Greek στίβι stibi through the Latin stibium as the former name for the mineral and the element antimony.

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<span class="mw-page-title-main">Ullmannite</span> Nickel antimony sulfide mineral

Ullmannite or Nickel glance is a nickel antimony sulfide mineral with formula: NiSbS. Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site. A solid solution series exists with the high cobalt willyamite.

<span class="mw-page-title-main">Alunite</span> Aluminium potassium sulfate mineral

Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite.

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12
Sb
4
S
13
. It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common. Other elements also substitute in the structure, most notably iron and zinc, along with less common silver, mercury and lead. Bismuth also substitutes for the antimony site and bismuthian tetrahedrite or annivite is a recognized variety. The related, silver dominant, mineral species freibergite, although rare, is notable in that it can contain up to 18% silver.

<span class="mw-page-title-main">Bournonite</span> Sulfosalt mineral species

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<span class="mw-page-title-main">Sperrylite</span>

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Pararealgar is an arsenic sulfide mineral with the chemical formula As4S4, also represented as AsS. It forms gradually from realgar under exposure to light. Its name derives from the fact that its elemental composition is identical to realgar, As4S4. It is soft with a Mohs hardness of 1 - 1.5, is yellow orange in colour, and its monoclinic prismatic crystals are very brittle, easily crumbling to powder.

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<span class="mw-page-title-main">Livingstonite</span>

Livingstonite is a mercury antimony sulfosalt mineral. It occurs in low-temperature hydrothermal veins associated with cinnabar, stibnite, sulfur and gypsum.

<span class="mw-page-title-main">Cervantite</span> Antimony oxide mineral

Cervantite is an antimony oxide mineral with formula Sb3+Sb5+O4 (antimony tetroxide).

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Stibiconite is an antimony oxide mineral with formula: Sb3O6(OH). Its name originates from Greek stíbi (στίβι), 'antimony' and kónis (κόνις), 'powder', alluding to its composition and habit. It is a member of the pyrochlore super group.

<span class="mw-page-title-main">Alacránite</span>

Alacránite (As8S9) is an arsenic sulfide mineral first discovered in the Uzon caldera, Kamchatka, Russia. It was named for its occurrence in the Alacrán silver/arsenic/antimony mine. Pampa Larga, Chile. It is generally more rare than realgar and orpiment. Its origin is hydrothermal. It occurs as subhedral to euhedral tabular orange to pale gray crystals that are transparent to translucent. It has a yellow-orange streak with a hardness of 1.5. It crystallizes in the monoclinic crystal system. It occurs with realgar and uzonite as flattened and prismatic grains up to 0.5 mm across.

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<span class="mw-page-title-main">Sarabauite</span>

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Guettardite is a rare arsenic-antimony lead sulfosalt mineral with the chemical formula Pb(Sb,As)2S4. It forms gray black metallic prismatic to acicular crystals with monoclinic symmetry. It is a dimorph of the triclinic twinnite.

Peretaite is a sulfate of antimony and calcium. The mineral, Ca(SbO)4(SO4)2(OH)2 (2(H2O)), was named Peretaite for its locality. It was first discovered in an antimony-bearing vein at Pereta, Tuscany, Italy.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 3 Handbook of Mineralogy
  3. 1 2 Mindat with location data
  4. Webmineral data
  5. Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN   0-07-049439-8