Amakinite

Amakinite is a semi-transparent yellow-green hydroxide mineral belonging to the brucite group that was discovered in 1962. Its chemical formula is written as (Fe2+, Mg)(OH)2. It is a trigonal-hexagonal scalenohedral mineral containing hydrogen, iron, magnesium, manganese, and oxygen.

It usually occurs in the form of splotchy, anhedral crystals forming within a group or structure in other minerals or rocks, such as kimberlite. Its composition is as follows:

  • Magnesium 5.82% Mg 9.66% MgO
  • Manganese 6.58% Mn 8.50% MnO
  • Iron 46.84% Fe 60.26% FeO
  • Hydrogen 2.42% H 21.58% H2O
  • Oxygen 38.34% O

Amakinite is slightly magnetic and was named for the Amakin Expedition, which prospected the diamond deposits of Yakutia.

General Information:

  • Formula: (Fe2+, Mg) (OH)2
  • Color: Pale green to yellow-green; rapidly turns brown when exposed to air, due to formation of Fe(OH)3
  • Hardness: 3½ – 4
  • Specific Gravity: 2.925 – 2.98
  • Crystal System: Trigonal
  • Name: For the Amakin Expedition, this prospected the Yakutian diamond deposits.

Physical Properties of Amakinite

  • Transparency: Translucent
  • Colour: Pale green to yellow-green; rapidly turns brown when exposed to air, due to formation of Fe(OH)3
  • Hardness: 3½ – 4 on Mohs scale
  • Cleavage: Poor/Indistinct observed in some grains
  • Fracture: Irregular/Uneven
  • Density: 2.925 – 2.98 g/cm3 (Measured) and 2.74 g/cm (Calculated)
  • Luster: Pearly
  • Magnetism: Weakly magnetic

 

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