Ruby Rock

Hope for rare gemstone

By GILES BROWN - The Press | 5:00AM - Wednesday, 01 July 2009

COLLECTOR: Gerry Commandeur with a piece of ruby rock he
has fashioned into a brooch. — GILES BROWN/The Press.

A West Coast gem-cutter hopes inclusion in an international reference book could raise the profile of one of New Zealand's most precious secrets.

Ruby rock is a stone containing ruby, sapphire and tourmaline, which is found only in the area roughly between Ross and Kumara.

Gerry Commandeur has been living in Hokitika for 10 years and was drawn there by the pull of ruby rock.

Dutch-born Commandeur moved to the area from Havelock, Marlborough, after he was shown a sample of the gemstone by a jade carver.

Commandeur, 72, said he recognised the "gem quality" of the sample.

This year ruby rock was included for the first time in the reference book Gemstones of the World, which is widely used by enthusiasts and experts.

Commandeur believes it could be another pull for tourists who already visit the area for its gold and jade.

The exact source of ruby rock, officially named goodletite after the man who discovered it, is not known, but Commandeur searched the area for samples.

Because ruby rock was dense and heavy, Commandeur said, it lay deep underground. He had never found a sample on the surface.

However, many residents of the area had lumps of the rock, which was found as a by-product of goldmining.

Commandeur bought all the ruby rock he could, and now runs a shop in the town selling jewellery made from it. He estimates he has enough left from the initial haul to last 20 years.

After that, the only way to find more may be to mine.

Ruby rock was first discovered in the late 19th century by William Goodlet, who was on a tour of the Schools of Mines on the West Coast.

He collected samples from the Back Creek area, near Rimu, and sent them to the University of Otago, where they were identified as true oriental ruby.

It initially caused a flurry of activity in the area amongst ruby-hungry prospectors.

Commandeur said three elements were needed to create the stone. "Heat, pressure and time. The heat is 400 degrees centigrade, the pressure is five kilobars and the time is three million years."

Ruby, sapphire and tourmaline form within the "mother rock", fuchsite. As the glaciers of the Southern Alps receded they left ruby rock behind in their moraines.

http://www.stuff.co.nz/the-press/news/west-coast/2553896/Hope-for-rare-gemstone