What grade are industrial grade diamonds?

[pyramid]

I have just read on an ebay chat board on ebay UK where a jeweller has stated that SI2-SI3 grade diamonds are "industrial grade diamonds only fit to grace the end of a drill." Is this so, I thought that was like I2 and I3 diamonds as I know even some I1 diamonds can look okay depending upon the inclusions?

 

[Richard Sherwood]

That's a snob remark.

Industrial grade falls below I3.

 

[Garry H (Cut Nut)]

Not always Rich.

e.g.
Some large clean brown goods are laser drilled and used for dies to draw round or fancy shaped wire.
Brown goods tend to wear rounded while white goods tend to wear to flat sides, and they cost less.

Large angular goods are also used on large diamond drill heads - often very big stones - the cost of pulling up an oil drill nearly a mile down to replace the drill head can be >$100,000, so they can afford to spend up big on the diamonds they use.