A guide to locating your all faceting rough and how to be a rockhound.
The world abounds in stones that are suitable for faceting. All you have to do is look, and know what kind of rocks to look in.
The most common crystals that are suitable are quartz. This mineral is found just about everywhere, and in every environment. As silica this is one of the commonest minerals found on earth.
In trap rock it is commonly found in vugs that are natural cavities found in the rock and are often lined with quartz crystals. The commonest crystals are amethyst which is a purple variety of Quartz. One of the crown jewels of France came from this kind of deposit in Nova Scotia in the cliffs on the west side of the Bay of Fundy in the town of Parsboro. This is still a notable location for finding gems and collecting minerals.
Probably more gems are found in pegmatites then any other suitable environment. Chemically, a pegmatite is nothing more than a granite intrusion that has been allowed to cool slowly growing very large crystals. Most of the pegmatites are called barren pegmatites because they usually don’t contain gemstones. Most of the gemstones in the world however, are actually found in pegmatites. This may sound contradictory but there is another kind of pegmatites called a dirty pegmatite. These are formed during the end of the intrusion cycle by the leftover compounds forced out of the granite intrusion as it cools. A dirty pegmatite contains many different gemstones and many other rare minerals.
One of these minerals is Beryl, a fairly common mineral that is beryllium aluminum silicate. Beryl crystals form a six sided long crystals they were called this by some of the mountain folk that live in the southern Appalachians because they looked like a gun barrel. Under its many guises beryl produces many different kinds of gems ranging from bright red to bright green. The bright green variety of beryl is the Emerald that is the most expensive of the gems. Other gemstones of the same family produce Aquamarine, Golden Beryl and Morganite it is pink. All of these stones with the exception of the Emerald are found in pegmatites.
Emeralds however are usually found in dolostone that has been intruded by a beryllium rich granite. The beryllium ions migrate from the granite into the dolostone where they crystallize out as emeralds. The other ingredient that makes the rich green of the Emerald is chromium with a dash of vanadium contaminating the crystals.
Another environment that needs exploring is the silica poor rock such as some lava and limestone. Rocks of this nature are the home of corundum if there is aluminum oxide present. Corundum is actually aluminum oxide, the crystals are hexagonal but unlike Beryl the sides of the Crystal are slightly curved this gives the corundum crystal the appearance of a barrel although; sometimes it forms a flat hexagonal crystal.
The ultimate flying is a diamond they are found in a rare intrusive rock called a kimberlite. If you are lucky enough to find a kimberlite with diamonds chances are you’ll die a billionaire. This is actually happened a few years ago in Canada. The commonest kind of crystal that diamond forms is the double ended octahedron. This commonly has small triangles formed on the surface with the apex of the triangle pointing in the opposite direction of the apex of the Crystal. Diamonds can be any color from the darkest black to water clear.
Although we have supplied you with most of the environments that produce stones most of the colored stones in the world are actually produced in placer mines by native workers. They are usually found in Third World countries but they also occur all over the earth except most people don’t have the patience to go looking for them. It wasn’t until recent times that the search for these gems has been mechanized. One of the companies producing these alluvial gems is Rockwell Diamond Inc. of South Africa. They are actively mining the sand and gravel deposits along the middle Orange River. Rockwell is an active diamond mine that is producing some of the largest, most perfect and expensive diamonds in the world. It
In this article we actually described what any Rockhound does; they are collecting gems and minerals. We hope you enjoy your new hobby!