Images
Formula: MgAl(SO4)2F.17H2O
Valence: MgAl(S6+O4)2F.18H2O (?18 instead of 17 IMA)
Hydrated sulphate, aubertite group
Crystal System: Triclinic
Specific gravity: 1.58 measured, 1.67 calculated
Hardness: 1 to 2
Colour: Colourless, white
Solubility: Soluble in cold water; will dissolve in its own crystal water if only slightly heated
Environments
Localities
At the Deputatskoe Sn deposit, Deputatsky ore cluster, Verkhoyansk Silver Province, Verkhoyansk Fold Belt, Sakha, Russia,
wilcoxite occurs in intensely oxidised cassiterite –
tourmaline – quartz –
polysulphide ore. Associated minerals include melanterite,
fibroferrite, gypsum,
goethite and ice
(HOM).
At the Rico Mining District, Rico Mountains, Dolores County, Colorado, USA, a sample of wilcoxite was collected
from the side of a timber crib, used in the past to load ore. The ores in the district are found in epithermal vein
deposits, porphyry-style
molybdenum deposits, and carbonate replacement deposits.
Secondary sulphate minerals directly associated with
wilcoxite at this locality are hexahydrite,
starkeyite and alunogen. All of
these minerals occur as efflorescence on the surface of waste ore found between the timbers of the crib where there is
some protection from rain and snow.
Wilcoxite occurs as a crust of anhedral clear crystals up to 0.3 mm in size. The crystals melt under the heat from
a microscope lamp and the resulting liquid then crystallizes to an amorphous solid
(CM 51.1.107-117).
At the type locality, the Lone Pine Mine, Lone Pine Hill area, Wilcox Mining District, Catron County, New Mexico, USA,
wilcoxite is a rare post-mine mineral deposited from solutions derived from an oxidizing
breccia zone. Associated minerals include
fluorite, gypsum,
khademite, lannonite and
pyrite
(HOM)
Wilcoxite from the Lone Pine Mine -
Image
Back to Minerals