[Sca-cooks] OT OOP Diamonds was tedious process

Terry Decker t.d.decker at worldnet.att.net
Sun Nov 25 13:50:37 PST 2007

Diamonds appear to have been found originally in India and Borneo.  They 
were known in Antiquity and the original finds are probably prehistoric.  I 
suspect the original finds were alluvial diamonds (washed out of the matrix 
rock and found in river sand).  Later finds are more diverse geographically 
and are usually associated with the erosion of igneous rocks to expose 
deposits of Kimberlite, a type of peridotite.  In 1970/71, I was in a 
prospecting class taught by Leo Mark Anthony, one of the best mining 
engineers in Alaska, when he showed slides of a series of Kimberlite pipes 
he had found in British Columbia while prospecting for tungsten.  I 
occasionally wonder if he wasn't the person who started the Canadian diamond 

In the 1st Century CE, Pliny associates diamond mining with Ethiopia, 
Macedonia, India, Arabia, and Cyprus.

Diamonds were considered valuable because of their rarity and their 
hardness.  A stone that can cut metal and other stones has amazing value. 
To quote Pliny, "The diamond, known for a long time only to kings and then 
to very few of them, has greater value than any other human possession, and 
not merely than any other gemstone." and "When a diamond is successfully 
broken, it disintegrates into splinters so small as to be scaracely visible. 
These fragments are greatly sought after by engravers and are inserted by 
them into their iron tools because the cut into the hardest surfaces with 
little effort."  There is archeological evidence of diamond bit drills being 
used in Yemen in the 4th Century BCE.

Diamonds have a square crystalline structure that in high quality stones 
translates into a rather flashy natural octahedral crystal.  A natural 
octahedral catches the eye quite nicely without facetting.  Since high 
quality natural stones are rare, diamond cutting produces an appealing 
gemstone from a more plebian diamond.  Diamond cutting in Europe probably 
starts in 14th Century Venice.  Facetting ehances the natural reflectivity 
of the stone.

For more on diamonds, let me recommend the American Museum of Natural 



> Do we know what areas diamonds were found in, in period? Since
> faceting of jewels was a late period invention, did diamonds even
> rank high on the scale of precious gems in period? I can easily see
> where other, colored, stones might have more value/interest, if you
> don't have faceting to bring out the gems "brilliance".
> Stefan

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