|Latitude & Longitude (WGS84):||32° 11' 14'' South , 119° 47' 41'' East|
|Latitude & Longitude (decimal):||-32.18741,119.79489|
|Köppen climate type:||BSk : Cold semi-arid (steppe) climate|
Gem grade pink tourmaline has been extracted from this site, however the pegmatite is intensely weathered. It is located 124 kilometres south of Southern Cross, in a gold and nickel mining region called Forrestania. The mine is presently (2012) leased by Fred Rose, who sells specimens from the mine on Ebay.
Kim Robinson accidently discovered the pegmatite while searching for nickel sometime between 1971 to 1976. Rubellite chips came up with the drill cuttings. He mined the site for tantalum in the early 1980's discovering the new species kimrobinsonite, which is an alteration mineral of stibiotantalite. During this time, about 200 kilograms of manganotantalite and microlite concentrates had been produced from approximately 3000 tonnes of ore. He also produced 1 400 carats of gem rubellite, and some of this was the finest gem-grade tourmaline produced in Western Australia. Mining ceased by the late 1980's and around 2000, the lease was purchased from Kim Robinson by Fred Rose, who has since conducted mining here for specimens.
The pegmatite is within a north trending greenstone belt, and both the greenstone and pegmatite are covered by a red-brown laterite layer. The pegmatite is 1-4 metres thick, dipping gently to the north, with a pit 75-150 metres long, 30-50 metres wide, and 18 metre deep, together with a small shaft near the north-western rim of the pit.
The pegmatite is severely weathered both physically and chemically, with much of the feldspars, albite and microcline, altered to clay. Further, fracturing and brecciation of unweathered core sections have altered some of the minerals left. What zoning can be seen show a hanging and footwall zone of medium grained albite-quartz with schorl, microcline-quartz intermediate zone, and quartz-cleavelandite-lepidolite core.
This central section has produced pink tourmaline, and rarely green tourmaline, clear quartz crystals and pink morganite. Fist-sized schorl crystals are said to be common at the west end of the pegmatite. Stibiotantalite and Kimrobinsonite are found in the underground workings. Kimrobinsonite is white, chalky, friable mineral to 5 mm, associated with black cesstibtantite (the first time the species was discovered in Western Australia).
One truckload of Giles Pegmatite rock was dumped at Mt Holland during the 1980's by Kim Robinson with the intent of processing it, composed of curly albite with columbite and muscovite masses. This material is said to be still found around the dumps, and does not belong to Mt Holland.
Co-ord 763041 mE, 6436217 mN
19 valid minerals. 1 (TL) - type locality of valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
2500 - 4000 Ma
|metamorphosed ultramafic rocks 74286|
Age: Archean (2500 - 4000 Ma)
Description: Metamorphosed komatiite, pyroxenite, chlorite-tremolite schist, talc-chlorite schist, anthophyllite-tremolite-talc rock; olivine-cummingtonite schist; talc-carbonate-tremolite-chlorite rock, serpentinite; amphibole schist after pyroxenite
Comments: igneous ultramafic volcanic; meta-igneous ultramafic intrusive; synthesis of multiple published descriptions
Lithology: Igneous ultramafic volcanic; meta-igneous ultramafic intrusive
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia). 
|Neoarchean - Mesoarchean|
2500 - 3200 Ma
|Archean crystalline metamorphic rocks|
Age: Archean (2500 - 3200 Ma)
Comments: Yilgarn Craton
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.