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Formula: Mg(AsO3OH).H2O
Hydrated arsenate,
koritnigite group
Crystal System: Triclinic
Specific gravity: 2.95 measured, 2.935 calculated for the empirical formula and 2.948 calculated for the ideal formula
Hardness: 3
Streak: White
Colour: Colourless to pale pink
Solubility: Slowly soluble in concentrated hydrochloric or nitric acid and very slowly soluble in concentrated
sulphuric acid
Environments
Magnesiokoritnigite is a relatively new mineral, approved in 2013.
Localities
The type locality is the Torrecillas mine, Iquique, Iquique Province, Tarapacá, Chile. The Torrecillas deposit
consists of two main veins rich in secondary
arsenic and copper minerals that
intersect metamorphosed marine shales and lavas.
Magnesiokoritnigite is associated with anhydrite,
chudobaite, halite,
lavendulan, quartz,
scorodite, canutite,
torrecillasite and at least two other potentially new
arsenate minerals. The assemblage is interpreted as having formed from the
oxidation of native arsenic and other
arsenic-bearing
primary phases, followed by later alteration by saline fluids
derived from evaporating meteoric water under hyperarid conditions. The metallic elements thus far identified in the
secondary minerals of this deposit include Na, Mg, Al, Ca, Mn,
Fe, Co, Cu, Ni and Sb
(MM 77.8.3081-3092).
Magnesiokoritnigite from the Torrecillas Mine -
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