Mineral Information and Data:

Phillipsite-Ca
Ca3(Si10Al6)O32 • 12H2O [CNMNC approved formula]

Named as the calcium-dominant species of the phillipsite series. Species named for William Phillips (1775-1828), English mineralogist and founder of the Geological Society of London. Name approved and defined per nomenclature for zeolite minerals (IMA, 1997).

IMA status : Approved Species 1998 ()
CLASSIFICATION 
Dana
(8th edition) :
77.01.03.06a  (This Dana# Added)
  (77) Tectosilicate Zeolite group
  (77.01) true zeolites
  (77.01.03) Gismondine and related species
  
Nickel-Strunz
(10th edition) :
09.GC.10
  (09) Silicates
  (09.G) Tektosilicates with Zeolitic H2O
  (09.GC) Chains of doubly-connected 4-membered rings
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Space group: P21/m
Unit cell: a = 9.9Å, b = 14.1Å, c =8.66Å; β = 124.75°, Z = 2
Crystal Habit: Crystals always twinned, pseudosymmetrical; striated || [001] on {010}, to 2 cm. Equant to prismatic, or in spherical radiating aggregates.
Twinning: Cruciform single and double penetration twins on {001}, {021}, {110}, ubiquitous
  
Color: White, reddish white, light yellow, pink
Diaphaneity: Translucent to opaque
Luster: Vitreous
Hardness (Mohs): 4 - 5
Measured Density: 2.2 g/cm3
Cleavage: {010} Distinct, {001} Indistinct
Tenacity: Brittle
Fracture: Uneven
Streak: White
  
Geologic Setting: Typically in cavities in basalt, of hydrothermal origin; an authigenic mineral in saline lake and hot spring deposits and calcareous deep-sea sediments.
Mineral Association: Zeolites, apophyllite, calcite, nosean, nepheline, olivine, melilite, celadonite
  

 

Phillipsite-Ca
Coating of colorless pseudo-octahedral shaped crystals.
Mineral identification confirmed by X-ray diffraction and chemical analysis.
Origin: Sasback on Rhine, Germany.
Photo: © RRUFF Project

 

Phillipsite-Ca
(zoom-in of above)

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