Tag Archives: crystals

Afwillite – a calcium nesosilicate

Afwillite

  • Named after the abbreviated discoverer Alpheus Fuller Williams (1874–1953), CEO of De Beers Consolidated Mines at that time
  • Formula: Ca3(SiO3OH)2 · 2 H2O
  • It belongs to the nesosilicates, i.e. there are only isolated SiO4 tetrahedra
  • Space group: Cc (No. 9)
  • Crystal system: monoclinic
  • Crystal class: m
  • Lattice parameters: a = 16.278 Å, b = 5.6321 Å, c = 13.236, α =  γ = 90°, β = 134.898°

Picture: Matteo Chinellato – http://www.mindat.org/photo-356015.html | CC BY-SA 3.0


Crystal structure (click on the pictures to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • Oxygen (red)
  • Hydrogen (white)
  • SiO4 tetrahedra (yellow)
  • CaO7 polyhedra (light blue)

For a 3D interactive version, see here:

https://skfb.ly/6J7oy

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Stibnite – a black make-up mineral

Stibnite

  • Synonym: Antimonite
  • The mineral has been known since ancient times and was used as a paste with fat as black make-up powder to color eyelids and eyebrows. In Arabic culture, dark eye rims are regarded as the ideal of beauty and at the same time as a magical repellent.
  • Formula: Sb2S3
  • Space group: Pnma (No. 62)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 11.3107 Å, = 3.8363 Å, c = 11.2285 Å, αβ = γ = 90°

Picture: DerHexer, Wikimedia Commons, CC BY-SA 4.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • SbS5 tetragonal pyramids (purple)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6JoCM


 

Valentinite

Valentinite

  • named 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.
  • Formula: Sb2O3
  • Space group: Pccn (No. 56)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters: a = 4.89960 Å, b = 12.4490 Å, c = 5.41030 Å, α = β = γ = 90°

Picture: Christian Rewitzer | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • corner-connected SbO3 pyramids (purple)
  • Oxygen (red)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6utNI

Thaumasite – a suprising mineral

Thaumasite

  • first described in 1878 in Sweden and named from the Greek, “thaumazein”, to be surprised, in reference to its unusual composition with carbonate, sulfate and hydroxysilicate anions
  • Formula: Ca3Si(OH)6(CO3)(SO4)
  • Space group: P63 (No. 173)
  • Crystal system: hexagonal
  • Crystal class: 6
  • Lattice parameters: ab = 11.0538 Å, c = 10.4111 Å, α = β = 90°, γ = 120°

Picture: Rob Lavinsky| iRocks.com  | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • CaO8 polyhedra (blue)
  • SiO6 octahedra (orange)
  • SOtetrahedra (yellow)
  • COtrigonalplanar coordination (gray)
  • Oxygen (red)
  • Hydrogen (white)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/6urWZ

Samsonite

Samsonite

  • Named after its type locality, the Samson Vein of Andreasberg silver mines, Harz Mountains, Germany.
  • Formula: Ag4MnSb2S6
  • Space group: P21/(No. 14)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 10.3861 Å, b = 8.1108 Å, c = 6.6630 Å, α = γ = 90°, β = 92.639°

 


Picture: Christian Rewitzer  | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • MnO6 octahedra (purple)
  • SbS3 trigonal pyramids (blue)
  • AgSdistorted tetrahedra (gray)
  • AgStrigonal-planar coordination (green)
  • Sulfur (yellow)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/69Hqz

Rodalquilarite

Rodalquilarite

  • Named after its type locality, the Rodalquilar gold deposit, Almeria, Spain
  • Formula: Fe2(TeO2OH)3(TeO3)Cl
  • Space group: P-1 (No. 2)
  • Crystal system: triclinic
  • Crystal class: -1
  • Lattice parameters: a = 5.103 Å, b = 6.653 Å, c = 9.012 Å, α = 73.40, β = 78.03° γ  = 76.76°

Picture: Christian Rewitzer  | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

 

  • FeO6 octahedra (brown)
  • TeO3 trigonal pyramids (blue)
  • Oxygen (red)
  • Hydrogen (white)
  • Chlorine (green)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/69DIu

Pascoite – a mineral with decavanadate anions

Pascoite

  • Named after its type locality Pasco Province, Peru
  • Formula: Ca3V10O28 · 17 H2O
  • Space group: C2/(No. 12)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 19.586 Å, b = 10.141 Å, c = 10.911 Å, α = γ  = 90°, β = 120.815°

Picture: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

 

  • Clusters of Decavanadate anions [V10O28]6- (orange)
  • CaO7 polyhedra (blue)
  • Oxygen (red)
  • Hydrogen (white)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/696Kr