Edward William Aldridge, for whom the mineral is named, was a publican in Broken Hill in the late 19th century.
Initially he had a very up-market hotel/pub that the miners did not patronise, but Aldridge was fascinated by
minerals, and wanted to buy directly from the miners, so he sold the posh hotel and bought another, humbler
drinking establishment which suited the miners better; they brought him their finds of fine
minerals, and doubtless some of what he paid for them was spent on booze in the pub. Aldridge amassed a formidable
mineral collection.
Images
Formula: (Cd,Ca)(Cu,Zn)4(SO)4)2(OH)6.3H2O
Sulphate, devilline group,
cadmium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.25 measured, 3.33 calculated
Hardness: 3
Streak: Pale blue
Colour: Pale blue
Solubility: Readily soluble in cold 10% hydrochloric acid
Environments
Localities
At the type locality, Block 14 opencut, Broken Hill, Broken Hill district, Yancowinna county, New South Wales,
Australia, aldridgeite is part of a suite of secondary
sulphate minerals that formed under late-stage supergene
low-temperature conditions. The following paragenesis is proposed:
antlerite → linarite
→ brochantite →
serpierite → ktenasite
→ connellite.
Solutions rich in copper, zinc,
cadmium and sulphur have been
derived from weathering of primary
galena, cadmium-bearing
sphalerite and
chalcopyrite.
Aldridgeite has formed contemporaneously with crystals of pale blue
niedermayrite in small cavities in a
quartz - garnet -
smithsonite matrix. The only other associated mineral is
pyromorphite, which forms tiny white prismatic crystals.
The aldridgeite occcurs as sprays up to 0.8 mm across of acicular crystals up to 0.4 x 0.005 mm in size and
often forming subparallel intergrowths
(AJM 17.2.67-71).
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