Inkamulla Sapphire Deposit, Spriggs Creek Bore (Spriggs Bore), Ambalindum Station, Harts Range (Harts Ranges; Hartz Range; Hartz Ranges), Central Desert Region, Northern Territory, Australiai

Regional Level Types
Inkamulla Sapphire Deposit	Deposit
Spriggs Creek Bore (Spriggs Bore)	- not defined -
Ambalindum Station	- not defined -
Harts Range (Harts Ranges; Hartz Range; Hartz Ranges)	Mountain Range
Central Desert Region	Region
Northern Territory	Territory
Australia	Country

The following information was copied from a 2012 Mindat discussion forum about Australian corundum. The information comes from Patrick Gundersen, and photographs of two specimens from the location are part of the thread. Mindat map is the bore itself, and the exact location is unknown and will probably remain that way. Access to Inkamulla Bore is by taking the track south immediately after the Plenty Highway crosses the Entire Creek. The bore is 22.6 kilometres south along this track.


'The corundum occurrence near Inkamulla Bore is hosted in the Entia Gneiss complex. These gneisses covers an area of approximately 160 km2 and are metamorphosed at intermediate temperatures (570-710°C) at peak pressures of ~ 7kbar and are postdating the regional granulite facies ordovician metamorphosis. The Entia Gneiss complex consists of supracrustal amphibolites, gneisses and calc-silicate rocks, of which kyanite is a characteristic constituent in many of the rock types. Corundum as microscopic grains has been identified both in amphibolites and a kyanite-biotite schist which contains almost 35%wt Al2O3 bulk chemistry. It is in one of these Al-rich kyanite-bearing schists, Patric Gundersen has found attractive corundum crystals:

"These Corundums were found in a VERY small outcrop of mica shist and kyanite, and to date I have only found a dozen or so specimens. They are all very well crystallized, with some intense dark blue patches (opaque sadly!) Many of the crystals feature a skeletal secondary growth of fine bladed Corundum, that forms cross-crossing lattice work across the top of the terminations and also extends beyond the edges of the crystal sides." Patrick Gundersen 2012

David Sheumack has had one of the corundum specimens analyzed by Ralph Bottrill. The XRD analysis shows that the corundum is partly altered to twinned white diaspore and some muscovite. It appears that this alteration is quite common on these corundums.'

Other Regions, Features and Areas containing this locality