Minrecordite


Composition: CaZn(CO3)2
Crystal System : Trigonal
Colours: Colourless, milky-white
Lustre : Pearly
Hardness (H) : 3.5
Specific Gravity (S.G) : 3.45
IMA Number: 1980-096
IMA Status: Approved
Discovered By: Gian Carlo Fioravanti (Italian mineralogist)
Named for: The Mineralogical Record magazine.

Tsumeb is the Type Locality

Distribution

Very rare. Second oxidation zone.

Occurrence

  • Supergene
  • 1st Oxidation Zone

Notable Finds

The type specimen is believed to originate from the middle of the second oxidation zone (29 through 32 levels).

Paragenetic and General Notes

Minrecordite is an inconspicuous mineral that is easily overlooked and very easily confused with dolomite. Analysis is required for verification; many alleged minrecordite specimens turn out to be dolomite!

Minrecordite forms minute, twisted, pearly, lustrous, colourless to milky-white, saddle-shaped rhombohedral crystals to 0.5 mm.

In specimen material, minrecordite from Tsumeb is invariably associated with dioptase, although there is apparently no reason why this mineral might not occur in other parageneses. 

Garavelli et al. (1982) propose the following mineralisation sequence for the "typical" minrecordite association:

(calcite + zincian dolomite + duftite) >> dioptase(I) >> magnesian minrecordite (sometimes with cerussite and calcite) >> minrecordite >> dioptase(II)