Glaucodot from Håkansboda, Lindesberg, Sweden. Size: 3.3 x 2.7 x 2.6 cm.
General
Category
Sulfide minerals
Formula (repeating unit)
(Co,Fe)AsS(Co0.75Fe2+0.25AsS)
IMA symbol
Gl[1]
Strunz classification
2.EB.10c
Crystal system
Orthorhombic
Crystal class
Prismatic (2/m) (same H-M symbol)
Space group
P21/c
Identification
Formula mass
165.15 g/mol
Color
Grayish tin white, Reddish silver white
Crystal habit
Massive , prismatic habits with elongated sphenoids, granular masses- Uniformly indistinguishable crystals forming large masses.
Cleavage
None
Fracture
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Mohs scale hardness
5
Luster
Metallic
Streak
black
Diaphaneity
Opaque
Specific gravity
5.9 - 6.01, Average = 5.95
Ultraviolet fluorescence
inert
Other characteristics
Nonmagnetic, non-radioactive
Glaucodot is a cobalt iron arsenic sulfide mineral with formula (Co,Fe)AsS. The cobalt:iron(II) ratio is typically 3:1 with minor nickel substituting. It forms a series with arsenopyrite (FeAsS). It is an opaque grey to tin-white typically found as massive forms without external crystal form. It crystallizes in the orthorhombic system. The locality at Håkansboda, Sweden has rare twinned dipyramidal crystals (see photo). It is brittle with a Mohs hardness of 5 and a specific gravity of 5.95. It occurs in high temperature hydrothermal deposits with pyrrhotite and chalcopyrite. Glaucodot is classed as a sulfide in the arsenopyrite löllingite group.
Glaucodot was first described in 1849 in Huasco, Valparaíso Province, Chile. Its name originates from the Greek Ancient Greek: γλανκός ("blue") in reference to its use in the dark blue glass called smalt.
Glaucodot is a cobalt iron arsenic sulfide mineral with formula (Co,Fe)AsS. The cobalt:iron(II) ratio is typically 3:1 with minor nickel substituting...
sulfur and arsenic in the sulfidic cobaltite (CoAsS), safflorite (CoAs2), glaucodot ((Co,Fe)AsS), and skutterudite (CoAs3) minerals. The mineral cattierite...
the vein deposits there. The cobalt minerals alloclasite, cobaltite, glaucodot and skutterudite have been found in very small amounts associated with...