Katsarosite

Katsarosite is a rarely occurring mineral from the mineral class of organic compounds with the chemical composition Zn(C₂O₄)·2H₂O and is therefore a water-containing zinc(II) oxalate or the zinc salt of oxalic acid.

Κatsarosite
Esperanza Mine, Kaminiza mines, Km 3, Lavrion Mining District, Lavreotiki, East Attica, Attica, Greece
General
Category	Mineral
Formula (repeating unit)	Zn(C2O4)·2H2O
Strunz classification	10.AB.05 10 : ORGANIC COMPOUNDS A : Salts of organic acids B : Oxalates
Crystal system	Monoclinic
Space group	2/m - Prismatic
Unit cell	a = 11.768(3) Å, b = 5.388(1) Å, c = 9.804(2) Å β = 127.045(8)°
Identification
Color	White to Yellow
Cleavage	Perfect on {110}, imperfect on {100} and {010}
Streak	Pale yellow
Diaphaneity	Transparent to opaque

Katsarosite is categorized in the humboldtine group as the Zn analogue of humboldtine (Fe(C₂O₄)·2H₂O). It is the second Zn-bearing oxalate mineral after alterite.[1]

Katsarosite crystallizes in the monoclinic crystal system and appears as crystals that are mostly fine granular to earthy, usually rounded with an average diameter of 30 μm. The color depends on the iron (Fe²⁺) content, ranging from pure white to yellow in Fe-rich specimens.[2]

The mineral is named after Īraklīs Katsaros (ΗΡΑΚΛΗΣ ΚΑΤΣΑΡΟΣ) of Lavrion who has led as guide a large number of scientific archaeological and mineralogical sampling tours through the ancient mining system of Lavrion. His help enabled more than 100 publications in the field of archaeology/mining history and mineralogy/geology. His assistance is further acknowledged in dozens of peer-reviewed scientific papers.[1]

Type material is deposited in the collections of the Institut für Mineralogie und Kristallographie der Universität Wien, Althanstrasse 14, 1090 Vienna, Austria, catalogue number HS13.977 (holotype); the Mineralogical Museum of Lavrio, Andrea Kordella Ave., 19500 Lavrio, Greece, catalogue number T3201 (cotype).