Mineralogy |
Page Updated October 20, 2006
This was the first mineral in which the element chromium was discovered.
Crocoite forms beautiful, fiery-coloured crystals, columnar to needle-shaped.
They occur in chromite deposits, quartz veins and in the oxidation zone of lead lodes.
Associated minerals are cerussite, pyromorphite and dundasite. Deposits are now only found in the Dundas area, neer Zeehan, on the West Coast of Tasmania.
The only other deposit of significance occured at Berezovskiy, near Sverdlovsk in the Urals.
Other, less abundant sources were Baita (Romania), at Labo (Luzon Island, Philippines),
near Congonhas (Brazil), Vulture (Arizona, USA), and in the Penchalong mine of Rhodesia, in Africa. Crocoite was first reported, in Tasmania, from the Heazlewood Mine to the North of Zeehan, the exact year
being in question, either 1885 or 1895. The Adelaide Mine is worked from underground. A new syndicate has taken over this mine from Frank Mihajlowits in recent years.
One of the cavities discovered at the Adelaide mine (by Frank Mihajlowits) in the early 1970's was 6 feet high,
8 feet long and 4.5 feet wide.
The walls, floor and roof were completely covered with crocoite crystals measuring up to three inches long.
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Name:
Chemical Formula:
Mineral System:
Hardness:
Specific Gravity:
Colour:
Lustre:
Streak:
Lead Chromate
PbCrO4
Monoclinic
2.5-3
5.9-6
Orange-Yellow
Greasy to Adamantine
Orange
Crocoite specimens are historically either from the Red Lead Mine or the Adelaide Mine at Dundas.
To the trained eye it is virtually always possible to distinguish which mine each specimen has come from.
These two mines occupy opposite sides of the same hill and are the source of the best crocoite specimens ever produced.
The Red Lead Mine has until recently been worked through an open cut section. Preparations are underway to recommence mining underground.
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All text and photographs copyright, 2001, by Shane Dohnt, unless otherwise noted.
Contact: shane@redleadmine.com
Last Updated October 20, 2006