It's A Diamond, Errr A Gregory?

Ever hear of a "Gregory?" Well, in South Africa, a British professor is immortalized forever, for his comment. In South Africa, a ‘Gregory’ is a term applied to a blunder of major proportions. Thanks to James Gregory, a professor from Great Britain. 

The story goes, that in the mid-1860s, diamonds were found along the Orange River in South Africa and Professor Gregory purportedly was hired in 1868 by a London diamond dealer, to investigate the Orange River diamonds to determine potential for the region to produce diamonds. After visiting the diamond fields, Gregory published a report in the Journal of Society of Arts, stating he had made a lengthy examinations of the new diamond fields and concluded there was no potential for mining diamonds as the stones were either ‘salted’ by locals attempting to increase the value of their farms, or transported to the Orange River by ostriches. Apparently Gregory never considered where all of the ostriches, decorated in rings, bracelets, necklaces, and tiaras were finding their gems. So the story goes, that within a short time, the Orange River region (its placers and kimberlites) became one of the greatest diamond producing regions in the world which included many of the greatest diamonds ever found on earth including the giant 3,006.75 carat Cullinan diamond. 

Two beautiful diamonds from Murfreesboro,
Arkansas. Note the distrinct greasy luster of the
raw diamonds (courtesy of Glenn
Worthington).

Unfortunately, Professor Gregory will not be the last pessimist. We’ve all known exploration geologists and company CEO’s who should have namesakes attached to blunders. Comments like … “if there was something of value, it would have already been found”, and “we only look in elephant country”, "the world will be ice free by 2013" deserve Gregory awards. Yet these types of comments are made by so-called educated people.  Prospectors on the other hand are optimistic - sometimes overly optimistic. An example of this optimism led to an interesting event when I was a geologist at the Wyoming Geological Survey at the University of Wyoming.  

Green octahedral diamond - a common crystal habit,
although green diamonds are not common.

I received a phone call from an individual who thought he had found a large diamond west of Cheyenne. According to an unnamed gemologist from Cheyenne, this crystal was large diamond. But the gemologist suggested before the prospector sold all of his belongings and purchased a mansion on the French Riviera he should visit my office for a second opinion. By this time in my career, I had a good reputation as a diamond exploration geologist because of my research on kimberlites and lamproites. At the end of the phone call, I gave him directions to my office. It’s about one hour’s drive from Cheyenne, so I was surprised when he and his three family members came knocking at my door 30-minutes later, apparently anxious to cash in their millions.  

The finder of the crystal introduced himself as ‘Jack’ and did not give a last name, and without further hesitation, opened a locked brief case chained to his wrist to show me the ‘Star of Cheyenne’. It was fist size, and about the same size as the famous Cullinan diamond. The Cullinan was the largest diamond found in history, and was a whopping 3,006 carats recovered from the Premier Mine, in Professor Gregory's old stomping grounds in South Africa. It was a priceless gem and ended up in the Crown Jewels of England. 

I had met Dr. Arnold Waters, Jr, a few years earlier in my office. Dr. Waters was the former Chief Geologist for DeBeers in South Africa, and Arnold told me that when the Cullinan was found, it had a distinct cleaved surface where part of the diamond had been broken during its transport to the earth's surface in a kimberlite pipe (volcano). He indicated the other half of the diamond was thought by some, to have been just a large if not larger than the Cullinan itself! Where it was - was anyone's guess. Did it break off somewhere at great depth and still sitting thousands of feet deep? Did it make it to the surface and was missed by the sorters ending up in the crusher where it made many little diamonds? 

Geologist examining rock sample with hand lens

The gem in question was gingerly handed to me. As soon as I saw it, I knew what it was, but decided to let the family down slowly, so I made a show of it. First I showed them how to test specific gravity of a mineral by weighing the gem in water then in air. I determined the crystal to have a specific gravity of 2.7 - too light for diamond (diamond's specific gravity is 3.5, heavy enough that it would show up with garnets and black sands in a gold pan). I also tested its hardness by taking a diamond chip and easily scratched a notch in the crystal. This resulted in an up-roar and immediate protest from the family as they thought I was scratching their priceless diamond.  

“Hold on a second,” I exclaimed.  “If this was a diamond, I wouldn’t be able to scratch it with a diamond chip so easily, diamond has a Moh’s hardness of 10 and is the hardest known mineral in nature, and it is almost impossible to scratch a diamond with another diamond”.  After I calmed them down and convinced them that all they had was an specimen of ordinary piece of rock crystal (transparent massive quartz), they left the office dejected and drove back to Cheyenne with visions of mansions and Lamborghinis fading.  I thought this was over, but I guessed wrongly.

The next day, I was contacted by one of our other geologists - Ray Harris (RIP) - who stopped in my office to tell me he had just received a call from a person in Cheyenne who had a probable diamond and wanted a second opinion. The person on the phone explained he had already talked to me, but he and his gemologist decided another opinion was a good idea.  

Ray went back to his office to wait for the Cheyenne family. I laughed to myself. Ray was a very good geologist, but he had a reputation as a klutz. He was famous for running into things, breaking things, and if anything could go wrong – leave it up to Ray. One of my favorite stories about Ray took place in a staff meeting. Ray was holding a cup of coffee in his left hand when another geologist asked him for the time of day. Without hesitation, Ray rotated his wrist to look at his watch, pouring all of his coffee in his lap. Ray was the Jacques Clouseau of geology.

Raw uncut diamond. Note the distinct trigons (triangular
growth plates on the diamond) this is characteristic
of many diamonds.

The Cheyenne family arrived with their gem. They talked about the gemologist’s opinion and their concern about my scratching their diamond. I don't know if Ray had ever seen an diamond in the rough and after examining the fist-size specimen with a hand lens, he decided to get a better look and carried it to his microscope in his adjacent lab. With family in tow, he lost control of the sample and it crashed onto the floor shattering into dozens of pieces.

The family turned pale white. But Ray consoled them as he looked down on the floor, “Well, guess it wasn’t a diamond – it has conchoidal fracture”.   

The family scooped up the fragments of their dreams and precious quartz and went home, never to be seen again. When Ray told me about this encounter – I delightedly laughed, and then pointed out to that diamond (as well as quartz) also produced conchoidal fracture upon breaking. Ray also turned pale white. But, I finished with, "don't worry it was just a piece of quartz".

* This story originally appeared in an article in the ICMJ Prospecting and Mining Journal as

Hausel, W.D., 2000, Diamond Fever: International California Mining Journal, v. 69, no. 6, p. 13-15. At the time, Ray Harris was still alive and a very productive member of society. However, within 6 years, he passed away after being harassed endlessly at the Wyoming State Geological Survey by the director. A very sad note for a person I admired and respected. Of a small staff of only about 24 people, 3 died, and about 40% resigned, retired or quit (all covered up by the Wyoming government & press).