Formula: NaCaCu5(AsO4)4Cl.5H2O
Hydrated arsenate containing halogen, lavendulan group, paramorph of lemanskiite
Specific gravity: 3.84
Hardness: 2½ to 3
Streak: Light blue
Colour: Lavender blue (Dana)

Hydrothermal environments

Lavendulan is a rare secondary arsenate in the oxidised zone of some copper arsenic deposits.


At Joachimstal, Bolivia, lavendulan is associated with erythrite (AM9.29-30).

At San Juan, Chile, lavendulan is associated with erythrite, cuprite and malachite (HOM).

At the Cap Garonne mine, France, lavendulan is associated with chalcophyllite, cyanotrichite, parnauite, mansfieldite, olivenite, tennantite, covellite, chalcanthite, antlerite, brochantite and geminite (HOM).

At Bou Azzer, Morocco, lavendulan is associated with erythrite. At Tamdrost it is associated with pharmacosiderite and arseniosiderite. At Méchoui it has been found in dolostone associated with chalcocite, covellite and conichalcite. At Ightem it is associated with conichalcite, and at Oumlil it is associated with erythrite and scorodite

(MinRec 38.5.381-382).

At Imiter, Morocco, lavendulan has been found associated with erythrite (MinRec 42.2.125).

At Tsumeb, Namibia, lavendulan is associated with cuprian adamite, conichalcite, o’danielite, tsumcorite, fahleite, quartz, calcite and gypsum (HOM).

At the San Rafael mine, Nye county, Nevada, USA, lavendulan is associated with scorodite (R&M 85.6.519).

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