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Formula: Ca(C2H3O3)2
Organic compound, glycolate subgroup,
hydronium mineral
Crystal System: Orthorhombic
Specific gravity: 1.85 measured, 1.879 calculated for the empirical formula
Hardness: 2½
Streak: White
Colour: Colourless
Solubility: At room temperature, insoluble in water but slowly dissolves in hydrochloric acid
Environments
Jimkrieghite is a new mineral, approved in 2023 and to date (February 2025) reported only from the type
locality.
Localities
The type locality for jimkrieghite, the Western end, Pusch Ridge, Pima County, Arizona, USA, is also the type
locality for lazaraskeite,
lianbinite, glecklerite
and stanevansite. Jimkrieghite occurs in a heavily fractured
leucogranite, 1 to 2 m below the rock surface. Associated minerals
include calcite, cerussite,
chrysocolla, hematite,
lazaraskeite, malachite,
microcline, mimetite,
phlogopite,
phosphohedyphane, quartz,
stanevansite and wulfenite.
Jimkrieghite is a secondary mineral believed to have
formed through the interaction of fluids containing glycolic acid (C2H4O3) derived
from decaying plant materials, plant root exudates or bacterial activities with Ca produced by the alteration of
primary and secondary minerals.
Jimkrieghite occurs as pseudo-cubic or thick tabular crystals, with individual crystals being up to
0.12 x 0.12 x 0.10 mm3 in size.
The most likely scenario for the formation of jimkrieghite and other
glycolate minerals, may be as follows: Underground water or fluids
containing glycolic acid (C2H4O3) derived from C3-type (where the first carbon
compound produced during photosynthesis contains three carbon atoms) plants flowed along cracks or fractures in
rocks, incorporating and carrying other elements with them. Given the relatively dry and hot weather in Arizona, as
well as the associated high elevation, such fluids would be expected to evaporate quickly, resulting in the
precipitation of various glycolate minerals; a relatively fast
evaporation process seems to be essential to keep glycolate from being oxidised to oxalate (oxalates are salts of
oxalic acid, H2C2O4). The fact that jimkrieghite and other
glycolate minerals have been discovered to date only in the desert
at a relatively high elevation points to a rather special geological environment for the formation of
glycolate minerals
(CJMP 63.91-101).
Jimkriegite from Pusch Ridge - Image
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