Prehnite is well known across Australia and a stone we like to claim as our own. It was the first gem to be named after a person but not after an Australian. Used as a talisman for protection, today it is known as the stone for dreaming or, in my case daydreaming…
First described in 1788 it was then later named ‘Prehnite’ in honour of Dutch naturalist, mineralogist and army officer Colonel Hendrik Von Prehn who was responsible for the discovery. Although first located in the Karoo dolerites of Cradock, Eastern Cape Province in South Africa, Australia is also a significant deposit site and this gem held magical properties for the native tribes of our dusty homeland.
Occurring as a secondary or hydrothermal mineral in veins or cavities, Prehnite is a hydrated calcium aluminum silicate Ca2AI2Si3O12(OH) with limited iron although Australian specimens often have brown ferrous coating which can be removed with chemicals. Crystalising in the orthorhombic crystal system, however tabular or prismatic crystals are quite rare, Prehnite is generally found in spectacular spherical and botryoidal masses, radiating fibrous aggregates and stalactitic formations. Famous for its yellow to green, grape-like coloration it can also be white, yellowish-brown, minty-green and bluish colours. Prehnite often has a cloudy-translucent appearance and displays a vitreous to pearly lustre on fractures and polished surfaces. Pieces with a fibrous structure can also display a weak cat’s-eye effect when cut in the correct orientation. With a hardness listing on MOH’s scale of 6 – 6.5 this stone is quite brittle although strong enough to wear as a ring.
Most Prehnite in Australia comes from the basalt tableland surrounding Wave Hill Station deposits in central Northern Territory within a small township called Kalkarindji. Stunning specimens have been fossicked from Wave Hill since the 1960’s but only recently has commercial quality and quantities been found. Australian Prehnite is unique in colour and lustre and far superior to the other locations around the world. Aboriginal people believed that Prehnite could absorb and store energies from the sun during hot and harsh days and rebirth the warm, positive light long after dusk has fallen to give protection from the creatures and spirits that lurk in the cold harsh Australian dessert nights.
Bunny Bedi, owner and designer at Made in Earth, is excited about his new Prehnite gemstone jewellery collection. “We’ve been lucky enough to get our hands on some spectacular Prehnite rough from Australia this year. This new rough gemstone displays excellent colour and the pieces we’ve cabbed so far have magnificent clarity and that vivid yellowy-green we love so much. It’s been a long time since we’ve had such wonderful high grade Prehnite and we are excited to launch our high quality Prehnite rings and pendants into our crystal jewellery collection.”
Australia may not have launched Prehnite onto the international mineral market, but our stones will certainly bring some heavy competition.
The title of “Gemologist” carries more than just knowledge and skills, it also suggests a person who is perpetually intrigued by the marvels of minerals and delicacy of crystallography and, I’d say, a fascination with the universe in general. Rocks and minerals leak a story of the past. As we study these million to billion-year-old specimens we can relive some of the conditions our planet has seen. More specifically, the microscopic investigation of inclusions in gemstones also tells a tale, where crystal has been, where it has come from and how old it is.
The Sikhote-Alin Meteorite is the largest observed meteorite fall in modern history. It is estimated that over 23,000kg fell that morning leaving behind 120 craters, the largest measuring 6 x 26 metres, with debris covering an elliptical area of 1.62km. The pre-atmospheric size of meteorite body was suggested to weigh over 1000 tonnes and more than 70 tonnes estimated to have reach the Earth’s surface. From this, 8,500 specimens have been collected, the largest weighing in at 1,725kg!
Kind of like a big-time celebrity who is notoriously private out of the public eye, Sapphire is one of those stones that absolutely everyone has heard about, but no one really knows anything about. “They’re the blue one’s, yeah?” Obviously not private in a Kardashian way, more like a Beyoncé situation. Yes, I just compared sapphires to Beyoncé; perhaps Kate (the Duchess of Cambridge) is more appropriate Bey is an Emerald girl after all.