Rainbow Caterpillar mine (Utnerrengatye; Rainbow Serpent Mine), Kong Bore Area, Mt Riddock Station, Harts Range (Harts Ranges; Hartz Range; Hartz Ranges), Central Desert Region, Northern Territory, Australiai

Regional Level Types
Rainbow Caterpillar mine (Utnerrengatye; Rainbow Serpent Mine)	Mine
Kong Bore Area	Area
Mt Riddock Station	Mountain
Harts Range (Harts Ranges; Hartz Range; Hartz Ranges)	Mountain Range
Central Desert Region	Region
Northern Territory	Territory
Australia	Country

A probable old mica-feldspar pegmatite working near Kong bore, found to contain "rainbow lattice sunstone". The mine name may not be formal; location very approximate.

The mine name may be the result of marketing by crystal healers.
The location has no connection with indigenous culture.

The mine owners have been reticent about revealing the exact location, other than near Kong Bore, for fear the deposit will be wiped out by fossickers. A look at the internet reveals this position is justified (I gave up after wading through ten pages of "Rainbow Serpent Sunstone" for sale). It is possible one of the other locations (Rochow, 1962), listed under Kong Bore is the same location. Specimens probably should be labelled as Kong Bore area.

The material was discovered in 1985 by Darren Arthur and Sonny Mason, and reported as a new gemstone material by the GIA in 1989. It remains its only location worldwide. However, sunstone is found at other locations including southern Norway, Sweden and various places in the United States including Oregon. These range from yellow, amber, orange, red in colour, some displaying aventurescence (glitter effect). Some Kong Bore material also displays this. However, it is the only location with a lattice effect. Sometimes it is called "Rainbow Lattice Sunstone."

It was originally described as a type of feldspar, "predominantly moonstone, with 75% orthoclase and 25% albite. The stones have inclusions of hematite and magnetite, orientated to form a lattice pattern. The hematite is small inclusions of yellow to deep orange hexagonal platelets providing the aventurescence. The magnetite forms thin blades along planes giving the lattice pattern, showing lamellar twinning and sagenitic twinning, and altered to give off iridescence, or the rainbow effect as it is popularly known as with this stone."

Other descriptions indicate oligoclase but this is unconfirmed. Recent analysis of some material from the mine (Bottrill, 2022) indicates quite pure microcline as the base of the gemstone, with inclusions of biotite. However XRD and SEM-EDS analysis on similar material sold under this name indicates beryl (R. Bottrill). There may be a variety of material, perhaps from different sources, being sold under this name.

The area was placed under a mining lease in 2017 for the sunstone, and fossicking may no longer be possible.

Other Regions, Features and Areas containing this locality

References