Kratochvilite: Properties and Occurrences

Kratochvilite is a rare organic mineral formed by combustion of coal or pyritic black shale deposits. It is a rare organic mineral, an orthorhombic hydrocarbon formed by combustion of coal or pyritic black shale deposits. It is a hydrocarbon with the formula of either C13H10 or (C6H4)2CH2.

It was first described from the Nejedly mine in Bohemia, the Czech Republic in 1937.

General Information:

  • Category: Organic mineral
  • Formula: C13H10 or (C6H4)2CH2.
  • Crystal system: Orthorhombic
  • Crystal class: Pyramidal (mmm)
  • Space group: Orthorhombic.

Fig: Kratochvilite

Properties

It is a polymorph of the aromatic hydrocarbon fluorene. It forms white, yellow to brown crystals in the orthorhombic system which occurs often as a druzy encrustation. It has a specific gravity of 1.21 and a Mohs hardness of 1 to 2.

  • Colour: White
  • Streak: White
  • Optical properties: Biaxial (+)
  • Density: 1.21
  • Hardness: 1-2 – Between Talc and Gypsum
  • Transparency: Translucent.

Occurrence: Formed as a result of burning pyritic shale (Kladno, Czech Republic).

 

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