Magnet Mine fossicking area
Collecting area and access
The old Magnet mine is located six kilometres directly west of Waratah in western Tasmania, although access is by a somewhat circuitous route. The mine is reached by traversing an unsealed road (the Magnet Road) leading off the sealed Waratah Road opposite Whyte Hill (on which a Telstra tower has been erected). This junction is approximately 12 km west of Waratah. The track is steep and badly eroded and is best restricted to 4WD vehicles.
The main collecting area is the ferromanganese gossan, which is located above the ruins of the old mill beside the access road (at AMG reference 370 100 mE, 5 410 650 mN). The collecting point is reached after travelling approximately 3 km along the unsealed road and passing through a gravel pit. The Magnet Road continues back to Waratah, but is almost impassable due to washouts.
The site is important as it is one of only a few accessible locations for crocoite and yellow cerussite.
This mine has been intermittently worked for silver, lead and zinc for many years, and more recently for specimen minerals. The primary ore consists of sulphide minerals in a banded carbonate vein in basic and ultrabasic rocks. There is an extensive oxidised zone developed above this, with many interesting secondary minerals in the gossan.
Minerals that can be collected on site include:
- Anglesite PbSO4 — occurs uncommonly as attractive white orthorhombic crystals to a few millimetres, with crocoite, pyromorphite and embolite.
- Argentite (acanthite) Ag2S — small patches and scales of this metallic grey mineral occur in galena.
- Arsenopyrite FeAsS — occurs commonly as small prismatic crystals to a few millimetres in vughs in siderite and quartz.
- Boulangerite Pb5Sb4S11 — this grey metallic sulphide usually occurs as fibrous or fine-grained bands with galena.
- Cerussite PbCO3 — this mine is famous for its ‘chrome cerussite’, which occurs rather abundantly as very attractive crystalline aggregates of yellow crystals, possibly coloured by traces of chromium. More normal white to colourless cerussite also commonly occurs at the mine.
- Chalcophanite (Zn,Mn,Fe)Mn2O5.2H2O — this mineral occurs as finely drusy masses of lustrous purplish black hexagonal crystals on psilomelane, with small cerussite crystals. It is also massive and dark brown.
- Chalcopyrite CuFeS2 — this mineral occurs as fine grains in primary ore, with sphalerite and siderite.
- Chlorargyrite AgCl — this mineral forms waxy masses and crusts, varying from yellow to green when fresh, darkening to violet brown with exposure to light. It is an important secondary silver ore in the gossans. It has been called ‘embolite’, the bromian variety.
- Chromite/magnesiochromite (Fe,Mg)Cr2O4 — occurs as small, lustrous, black crystals to one millimetre in the green country rock.
- Crocoite PbCrO4 — this mineral occurs rarely as attractive, fine, monoclinic prismatic crystals to 50 mm, with a bright orange to red colour. The crystals occur as entangled masses, as single crystals on gossan, or intergrown with yellow ‘chrome cerussite’. Terminated crystals, unusual for this mineral, also occur.
- Dolomite Ca(Fe,Mg)(CO3)2 — common as a gangue mineral in the primary ore, with a white to brown colour, often described as ankerite. These banded ores may make attractive specimens.
- Galena PbS — this metallic grey mineral with perfect cubic cleavages was an important primary ore of lead, and is still common.
- Goethite FeO(OH) — an important constituent of the gossans. Usually massive, powdery yellow to brown and black when massive.
- Greenockite/hawleyite CdS — this occurs as a bright yellow powdery coating on gossan.
- Lepidocrocite FeO(OH) — this mineral occurs as red patches with anglesite on goethite.
- Mimetite Pb5(AsO4)3Cl — relatively common in the gossans as small, colourless to yellow, orange, red and brownish-green hexagonal prismatic crystals, containing a little chromium. Sometimes described incorrectly as vanadinite, endlichite, pyromorphite or carminite.
- Muscovite KAl3Si3O10(OH)2 — the green, Cr-rich variety ‘fuchsite’ can be collected in altered wallrock samples on the dumps.
- Phosgenite Pb2(CO3)Cl2 — another rare secondary lead mineral recorded in the gossans as rather large adamantine, brown to colourless crystals on galena. Rarely reported, but probably mistaken for anglesite or cerussite.
- Plumbojarosite PbAl6(SO4)4(OH)12 — this powdery yellow-brown mineral occurs uncommonly on gossan.
- Proustite Ag3AsS3 — this ‘ruby silver’ mineral was reported as rare prismatic hexagonal crystals and thin coatings, sometimes with native silver. The fresh mineral is an attractive scarlet vermilion, but darkens to black with exposure to light. It has reportedly been recently collected.
- Pyrargyrite Ag3SbS3 — this ‘ruby silver’ mineral is very similar to proustite in appearance and occurrence. It was reported here as rare crystals and in association with galena and native silver.
- Pyrolusite MnO2 — this powdery brown-black mineral occurs in the gossan.
- Quartz SiO2 — fine quartz crystals occur in some veins.
- Rhodochrosite MnCO3 — recorded as a primary mineral in the ores, sometimes termed ‘manganosiderite’, grading into siderite. A pinkish mineral with pearly cleavages.
- Romanechite (psilomelane) BaMn9O16(OH)4 — this mineral is present in the gossans as massive or stalactitic, hard black material.
- Siderite FeCO3 — recorded as a primary mineral in the ores, sometimes termed ‘manganosiderite’, grading into rhodochrosite. A brownish mineral with pearly cleavages.
- Silver Ag — ‘native’ silver was an important secondary mineral in this deposit, where it occurred as hair-like patches in sphalerite. It is a silvery metal, often tarnished grey or black.
- Sphalerite ZnS — common in the primary ores with galena, siderite, etc. It is black and coarsely crystalline, with good cleavages.
- Smithsonite ZnCO3 — this mineral is rare in the gossans, but occurs as translucent grey hexagonal-rhombohedral crystals lining cavities.
Other reported minerals (not all confirmed) include:
Historic mining relics occur in this area. Fossickers are asked to respect these relics by avoiding disturbance of historic workings and not collecting artefacts (e.g. bottles, pieces of machinery, etc.) from this area.