GIA Clarity Grading Question - "Etch Channel"

[kenny]

What is an "Etch Channel"?

This is from a GIA Colored Diamond Grading Report dated Feb 22,2012 for a natural Fancy Red diamond.

http://www.fancydiamonds.net/view_diamonds/6075.htm

 

[diagem]

Never seen that Kenny,

Maybe https://www.pricescope.com/communit...-etched-diamonds-for-fire-enhancement.131255/

 

[Lotus99]

This abstract may help with the definition: http://www.sciencedirect.com/science/article/pii/S0925963500004076

The full article is behind a paywall, unfortunately.

I'm no expert with diamonds, but the definition may help you understand what it is, at least on some level.

 

[0-0-0]

Sounds like they are essentially surface reaching growth tubes?

This article has some related info, but it's too bad the image links are dead: http://www.diamonds.net/news/NewsItem.aspx?ArticleID=3899

A variation to this process involves cutting a channel into the diamond with what appears to be several drill holes placed side-by-side which end up looking something like a natural etch channel a first glance. Acid bleaching is done through these channels, which are cut to reach internal feathers or dark crystals. In the small number of samples we have seen, this specific procedure has originated near the girdle or in the crown facets. Interestingly, this is also the area where natural etch features are most frequently located. Careful examination with a gemological microscope reveals the dissolution features of the crystal on the faces of natural etch channels in untreated diamonds. Although dull, frosted, or glassy in appearance, the "side walls" of the laser created features do not have the same angular characteristics that occur in natural etch channels

 

[tyty333]

Someone made a boo-boo while etching the cert number on the girdle.

 

[0-0-0]

Found a picture of GIA etch channels, but not in a diamond.

http://www.gia.edu/research-resources/gia-gem-database/scapolite-34149.pdf

 

[slg47]

Lotus I was about to link the same article. I was able to access the full pdf since I am logged on with the proxy server of my school.

this post mentions a diamond with etch channels filled with iron sulfides
" The Lab Notes section presents recent discoveries from the GIA Laboratory, such as apatite inclusions in spessartine and a diamond with large etch channels filled with iron sulfides. "
http://www.gialondon.co.uk/news--events/document-34-21.php

 

[dynastyice]

Etch channels are hollow tube, that has is a surface reaching inclusion. Has an opening to the surface.

 

[Leibish & Co.]

Hi Kenny,

Great question, etch Channel isn't a very common definition....

The term “Etch Channel” will be used to document a hollow channel in the diamond that extends inward from the surface. It occurs naturally and is thought to be the result of high temperature igneous fluids etching out a weak area as the diamond travelled toward the earth’s surface. As with other surface-reaching inclusions, these will be plotted where they break the surface.

Hope this helps...

Itzik Polnauer

 

[kenny]

Fascinating!!!

Thanks all.
So much to learn.

Etch channels must be very rare.

 

[Christina...]

Hi Kenny! I was just doing some research because I came across a stone that also has an etch channel and had no idea what it was. This report is interesting because it also notes that the stone has a 'patch of color' and I hadn't seen that listed on a report before.

http://www.jamesallen.com/diamonds/J-SI2-Very%20Good-Cut-Round-Diamond-1462094.asp

 

[kenny]

Thanks Christina.
How fascinating.

I used JA's "virtual loupe" to try to find the EC but I didn't know what to look for.
Also the GIA plot only indicates it is on the bottom so I'm not sure it would even necessarily be visible from the top.

And that patch of color . . . hmm.
I wonder if it's green because I hear many if not most green roughs have the green color only near the skin, which of course gets polished almost completely away if they leave a natural.

 

[platinum350]

Sorry to dig up an old thread but did anyone figure out if an etch channel has a negative impact on a diamond? I found a diamond I like but it's GIA report says it has one.