Lots of people enjoy going to fee mining sites where you can prospect inactive surface mines, mine tailings, soil, sediments or outcrops and keep any rocks, gems, minerals or fossils that you find. Examples include: Herkimer Diamond Mines where you can search for doubly-terminated quartz crystals, and Crater of Diamonds where you might be lucky enough to find a real diamond.
How diamonds form is one of the most common geological misconceptions. Diamonds form under a variety of conditions that rarely, if ever, involve coal as a source of carbon. In fact, most diamonds formed long before the first coal swamp or land plant!
Several factors work together to determine the annual value of Australia’s diamond production. The output of mining operations, the quality of the stones, world diamond prices, and the relative strength of the Australian Dollar against other currencies are major factors in the annual value.
The impact occurred where Archean graphite-garnet gneiss basement rock was overlain by about 1.5 kilometers of sedimentary cover. [...] Diamonds formed and survived in a thin zone of rock located about 12 to 13.6 kilometers out from the point of impact.
Undisclosed synthetic diamonds and color treatments are a huge problem in the diamond trade. The Gemological Institute of America now has a low cost method to screen and document the nature of small diamonds.
Rio Tinto is looking for buyers for three diamond mines. A 100% stake in the Argyle Mine in Australia that is famous for its pink diamonds, a 60% interest in the Diavik Mine in the Norwest Territories of Canada that is famous for it’s extremely high ore grade, and the smaller Murowa Diamond Mine in Zimbabwe.
Most people don’t realize that some amazing emeralds have been found in North Carolina. The North Carolina Museum of Natural History just received a gift of four emeralds found in Alexander County in 2011 that are worth millions of dollars.
Low diamond prices and a strong Australian dollar have caused problems for the Australian diamond and gemstone mining industry for the past five years (see graph below). Could 2012 be a year of change?
De Beers Canada has an agreement with the Province of Ontario that ten percent of the gem quality diamonds produced from the Victor Mine will be cut in Ontario. The problem is finding cutters who have skills that match the quality of the stones.