Clarification of appearance

[pyramid]

I have just read that cleavages in diamond can have different appearances but it does not show or explain what these are. Can anyone explain what the different appearances would be?


Here is the quote:

"There really isn't different types of cleavages, they can be located at different places through out the diamond, and they can be very small or very large, they also can have different appearances."

 

[valeria101]

----------------
On 2/3/2004 5:34:47 AM pyramid wrote:


'There really isn't different types of cleavages, they can be located at different places through out the diamond [...].'
----------------

Pyramid, where is this from?

I don't know what to think of: cleavage plane, cleavage direction, twinning planes, fractures or growth marks? Gem materials (and all crystals) are classified according to a few types of cleavage, and in diamonds cleavage varies with the type of crystallyzation. So if the source cites says that “cleavage is of one type” we are talking of different animals altogether. The citation uses some kind of "gem lingo" I have yet to come across...

 

[pyramid]

I found this quote in a diamond internet article. They were referring to cleavage fractures/cracks I think. I cannot find the article again though.

 

[Garry H (Cut Nut)]

I saw a cleavage with a diamond nestled comfortably between them today and they were far better than Janet Jacksons.
But then it is summer here and the girls are not wearing much

 

[pyramid]

woo hoo, ha ha

 

[valeria101]

Ouch!

 

[pyramid]

Would the appearance of a cleavage crack in DIAMOND

be like rough diamond with a matt appearance like an unpolished girdle or are there really different appearances?

 

[valeria101]

Pyramid, "cleavage" is not a "crack", maybe "feathers" is what you have in mind? Or "fractures" ? I really thing "feathers" is the answer, and well, many enough of those (as industrial rough below gem grade) would dull a diamond crystal into a crackled, "white" mass.

Scattered white inclusions, fine enough not to be identifiable with standard magnification (I guess this refers to 30X), make some diamonds "milky" or opalescent - depending on the density of inclusions and who-knows-what else (Garry’s webpage on colored diamonds has a note on these, not sure where else to point out data on them).

If you get enough white inclusions of all sorts in a crystal, it will look just plain white, but I have not yet came across a plain white and opaque diamond looking like chalk. There are allot of opaque diamonds, and the "coating" or skin of some white rough has the look of sugar cubes... 'cause there are many small crystal facets playing with light and plenty of white "inclusions" below them.

What is all about?

 

[pyramid]

Thank you for this information valeria101. Yes I think it is the same as feathers.

 

[pyramid]

By the way, what is the difference between a feather and a fracture?

found it


feather
Cleavage or fracture; may be transparent, but usually has a
whitish appearance when seen at right angles to the break.
Also called a gletz.
From the GIA Diamond Dictionary (3rd Edition), Copyright 1993 by GIA