Moolooite: Properties and Occurrences

Moolooite is a rare blue-green mineral, a hydrated copper oxalate with an orthorhombic crystalline structure. It is a mineral with the formula Cu++(C2O4)·n(H2O) (n<1) (copper oxalate hydrate). It was named for the original locality on Mooloo Station, Australia.

It is a naturally occurring hydrated copper oxalate from Western Australia It was discovered by Richard M Clarke and Ian R Williams in Bunbury Well, Mooloo Downs station, Murchison, Western Australia in 1986.

General Information

  • Category: Oxalate mineral
  • Formula: (repeating unit) Cu(C2O4)·0.4H2O
  • Strunz classification: 10.AB.15
  • Crystal system: Orthorhombic
  • Crystal class: Dipyramidal (mmm)

Moolooite – a rare blue-green mineral


It has an orthorhombic crystalline structure and is formed by the interaction of bird guano with weathering copper sulfides. It is used in plastics to color them blueish-green.

  • Color: Blue, Green.
  • Density: 3.43
  • Diaphaneity: Transparent
  • Habit: Microscopic Crystals – Crystals visible only with microscopes.
  • Luster: Earthy (Dull
  • Streak: light blue


On an outcrop of quartz, thought to have formed by the reaction between bird guano and soluble secondary copper minerals (Mooloo Station, Australia); in a mine shaft near tree roots (Sainte-Marie-aux-Mines, France). It occurs as micro-concretionary crusts and powder in cracks and solution cavities resulting from sulfide oxidation.

A second occurrence is reported from the Sainte-Marie-aux-Mines silver mining district of Vosges Mountains, France.

Association: Opaline silica, sampleite, libethenite, brochantite, antlerite, atacamite, whewellite, chalcopyrite, digenite, covellite, gypsum, barite, jarosite (Mooloo Station, Australia).