|Diamonds are isometric (equal-dimensional) and typically have|
crystal habits of a octahedron or some modified version.
Being suspicious because I've heard so many similar claims, I asked the prospector how he was identifying them?
His response - "I just scratch the windshield of my truck"
I responded, "Are you going to be able to drive home safely?"
On the other end of the phone was silence as he was thinking about this 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 hardness scale that is relative and specific minerals have been assigned relative hardness. Diamond tops the scale at 10.
In my upcoming book with the working title of 'Rocks in My Boots - A Prospector's Guide to Gemstones, Precious Metals, Rocks, Minerals and Tall Tales' that will hopefully be available at Amazon in late 2014, I discuss this problem. Some of us 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, that the glare was making it difficult to see out? 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. This tells us that diamond is harder and will scratch you window, but so will corundum, topaz, quartz, and even most feldspars. And mixed in-between these minerals from feldspar to diamond, are hundreds of silicates like amphibole and pyroxene. So, please do not scratch your windshield as a test. Instead, either learn the minerals' physical properties, 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.
|Kimberlite (note the emerald green chromian diopside). Just about every kind|
of rock has been misidentified as kimberlite by prospectors. It is not easy
to recognize and one must be aware that many rock types will have the same
color as kimberlite - kimberlite comes in many colors. Color is NOT the
defining characteristic for this host rock of diamond. This sample was
collected from a diamond-bearing kimberlite in Colorado.
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 assist you in this endeavor, I put together two websites - one specifically on diamonds, the other on gemstones along with some blogs and my new book will also tell you how to identify the host rocks.
You can find more information on diamonds and their host rocks from free downloadable publications on my website and at your local library.