Wednesday, April 30, 2014

How to Recognize Rough Diamond

My book on Finding Gemstones is published and I've heard back from a few prospectors who have had the chance to use it, I am optimistic the book will lead to several gemstone discoveries. One prospector reported he had found a large number of diamonds including one, flawless, 6-carat diamond, just by panning near the Sloan kimberlites in Colorado! Later, I was contacted by a prospector who found a cache of diamonds in North Carolina based on this and another book I wrote in 1998 on diamonds in the US. So, get a copy and get out looking for some gemstones!

Still another found several precious opals and some fire opal and another reported a new sapphire deposit. Several others have sent letters and photos of the spectrolites and moonstones they found because of my book - and these are just a few of the people who are out there prospecting and using my book.

"Diamonds, diamonds, diamonds - I'm finding them everywhere I look"! Being suspicious because I've heard so many similar claims, I asked the prospector how he was identifying them?  
Diamonds are isometric (equal-dimensional) and typically
have crystal habits of a octahedron or some modified version.
Photo copyright by W. Dan Hausel@Gemhunter.webs.com

His response - "I just scratch the windshield of my truck"

I responded, "Are you going to be able to see when you drive home?"

On the other end of the phone was silence as he was conteplating my comment - guess it wasn't what he expected.  

Diamonds are hard. They are considered the hardest natural mineral, although there are some extremely rare forms of carbon that are even harder. Even so, diamond will scratch your windshield. When geologists discuss mineral hardness, one simple scale which is often mention is that of Moh's scale. This is a relative hardness scale and specific minerals have been assigned relative hardness from 1 to 10. Diamond tops the scale at 10. 

In my new book entitled 'A Guide to Finding Gemstones, Gold, Minerals and Rocks', I discuss the hardness of diamond as well as problems that prospectors have in identifying diamonds. Many have the impression that what ever scratches glass is diamond. Well, this is only partly true. 
Some of the common indicator minerals associated with diamond include
pyrope garnet, chromian diopside, olivine and a few other minerals. Note
all of these that I collected in Wyoming are gem-quality.

Have you ever replaced your windshield in the windy states of Arizona or Wyoming because your windshield became so pitted by blowing dust that the glare off the pits was making it difficult to see? Now think about this, has your windshield been bombarded by thousands of tiny diamonds?  

It turns out that a windshield on a car (or a prospector's truck) has a Moh's hardness of only 5.5 to 6.0. It's true that diamond is harder and will scratch your window, but so will corundum, topaz, quartz, most feldspars and many other silicates like amphibole and pyroxene. So, please do not scratch your windshield as a test. Instead, learn the physical properties of this mineral, or use something that eliminates the problem - something that jewelers use all the time - a 'Diamond Detector'. You can find these detectors on eBay for very reasonable prices.

Beautiful, flawless diamonds in the rough from the Argyle Mine in Australia.
Photo "Copyright © 2014 Rio Tinto.".
But as far as the host rocks and the beautiful 'diamond indicator minerals' associated with many diamonds, you will need to study their physical properties and characteristics to be able to recognize them. To assist you in this endeavor, I put together websites - one specifically on diamonds, the other on gemstones along with several blogs and my new book found at Amazon.

You can find more information on diamonds and their host rocks from free downloadable publications on my website and at your local library