Georgiadesite , Paralaurionite Locality: Vrissaki Point slag locality, Vrissaki area, Lavrion District slag localities, Lavrion (Laurion; Laurium) District, Attikí (Attica; Attika) Prefecture, Greece Monoclinic georgiadesite crystal on tabular paralaurionite xls. Picture width 3 mm. Collection and photograph Christian Rewitzer This Photo was Mindat.org Photo of the Day - 4th Mar 2010 — Photo: Christian Rewitzer · CC BY-SA 3.0
Georgiadesite
Georgiadesite is an IMA-recognized mineral species in the halide class, with the chemical formula Pb₄(As³⁺O₃)Cl₄(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 3.5; specific gravity 6.3; Resinous luster; optically biaxial.
IMA symbol Ggd, grandfathered status — known before the IMA’s founding, named in 1907.
Formed by the action of seawater on lead-bearing slag (Laurium, Greece).
It is found associated with Laurionite, fiedlerite, matlockite, phosgenite, nealite (Laurium, Greece).
In honor of Mr. Georgiadès, a Director of the mines at Laurium Greece.