FMF - Friends of Minerals Forum, discussion and message board

[simonoff]

We picked up a small aquamarine crystal while in Tucson because it looked interesting, something we wanted to study. Now that we have, of course, unanswered exist I am hoping you can help with.

Lots of questions here (most raised by my daughter)....

- Are these really etching pits.
- Why are they running up and down the crystal's prism faces - at what appear to be almost even intervals
- What chemicals cause the etching in beryl

Basically we'd love to learn a lot more about these.

Thanks for any help anyone can provide.

Bob & Jessica

[Jason]

yep..i have had some cool ethced aquas from many locations..i think the etching is normally caused by hydrogen flouride or potassium flouride in the water vapor stage during pocket formation..will have to double check my facts but i think after some study of etchings on Mt. Antero aquas that was the conclusion..probably different for other locations..but the only unresolved issue was if it was HF which at first they thought it would have etched accompying quartz crystals, feldspar, and mica and many times those were pristine..so pockets that had etched beryls many times had unetched other minerals..not sure if they solved that conundrum

[jacquestouret]

For beryl (not only aquamarine!) etching, the fluorine track is most probaly good. For those who want to go a bit deeper, see the work of B. Moine et al. on Madagascar emerald deposits (C.R. Geoscience, vol. 336, n°6 (2004) , p. 513-522 (in French, but with a significant english version). Several other papers by this group (Toulouse) on the subject. Note also that spectacular blue beryls almost completely dissolved appear now regularly on the market, many of them from Pakistan ?.

[John S. White]

Jacques:

I believe the vast majority of the deeply etched blue beryls are from Pedra Azul, Minas Gerais, Brazil. I have a small one and that is the locality information I have for it.

[Matt_Zukowski]

Those etchings look to me like the pattern one sees on the Volodarsk-Volynskii beryls.

[olelukoe]

Ye - some times so interesting figures of etching on a beryl crystals surface we can see, for example:

[Peter]

Jessica and Bob

The etching certainly is a most interesting subject and I am not surprised on your curiosity. To be curious is the most important thing in life.

To put it shortly, the shape of the etching will depend on what face the etching occurs in and the etching media. This etching is typical for the edges. Hexagonal etch pattern typical for the pinakoid (flat top) termination. A multitude of forms for other faces, as we are "attacking" the beryl molecule from different directions.

Jogn Sinkankas was an exceptionally talented scientist, mineral collector, gem cutter, observer, student and teacher. PLease do buy his book. Emerald and other beryls.
It is one of the most valuable books I ever got. So many answers and leads to many questions!!! In the chapter checmical and physical properties he summaries many good references and research into beyl etching, also laboratory trials and study of natural crystals.

One researcher (Honess) obtained "satisfactory" etch figures on beryls in 15 seconds by immersing them in moltensodium hydroxide where boling hydrofloric acid for an hour failed to produce the slightest trace of etch figures (page 277 and 268).
I have many examples of interesting groths and etch figures.
Best regards
Peter

[Jason]

Wow that last heliodore etching..are you sure thats etching and not ancient sumerian writing..LOL..stuff looks cool

[Peter]

That last one is a "message from outer space from a civilization 490 million light years from us", or at least that is what some people would believe and try to prove if the picture would reach them ;)

[simonoff]

Careful Peter - words like that could start a whole new mineral sales industry.

[Jason]

I still wish I had this Antero aqua..it had some of the coolest etching on it..sold it awhile back..sigh..sure wish i had a pic of it..some awesome designs

[Jessica Simonoff]

The first photo that Olelukoe posted looks like it has a pattern in it which has a similar shape to the shape of the etching in this aquamarine. Do you know what makes the etching create different patterns?
Thanks