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Andradite (y)?

Posted by James Christopher  
avatar Andradite (y)?
February 26, 2012 03:03PM
I bought an andradite, var melonite at a show yesterday. It was labeled andradite(Y). I am assuming the dealer, or whoever he got it from, was confusing the Y site with yttrium. Am I correct in this assumption, or is there a yttrium containing andradite? It is from Ojos Calientes mine in Mexico.
avatar Re: Andradite (y)?
February 26, 2012 04:47PM
Are you sure there is a "Y" after the name and not a "M" or "T"? "M" could be for melanite, "T" for titanoan. There is not a locality called "Ojos Calientes Mine" in Mindat. Perhaps it means "Ojos Espanoles Mine".
It will help if you can post a picture.

Re: Andradite (y)?
February 26, 2012 06:05PM
Yttrium does fit into garnet-type structures, as witness the synthetic garnets like YAG, used as gemstones. Yttrium-bearing andradites are known in nature too, in Japan, and a mine in Chihuahua, Mexico. But only the writer of your label knows what the "(Y)" stands for in your case... yttrium? Initial of the name of the person who dug it up? catalogue organizer? I wouldn't assume it necessarily refers to the element.
Re: Andradite (y)?
February 26, 2012 06:32PM
Hello James,
If you drop the "s" in "Ojos" and search Mindat for Ojo Caliente you'll find, in Rio Arriba Co, NEW Mexico, garnet along with a good suite of REE minerals. My guess would be Ojo Caliente Dist. Rio Arriba Co., New Mexico.

avatar Re: Andradite (y)?
February 26, 2012 07:01PM
I have a sample in my collection of "yttrian garnet" from mexico. it's black, can't tell you more about it until I get a chance to look into my catalogue.

avatar Re: Andradite (y)?
February 26, 2012 07:34PM
There is also a Mun. de Ojo Caliente, Zacatecas, Mexico, however no garnets are currently listed as found there.


Andradite from La Prieta Mine, Chihuahua are indicated as yttrium-rich.


Re: Andradite (y)?
February 26, 2012 09:47PM
The term "YAG" refers to yttrium aluminate, garnet structure.

It is certainly NOT a garnet to we mineral people.

I use cerium doped yttrium aluminate from Union Carbide to make electron detectors.

Union Carbide sold it as a laser material.

The cathodoluminescence from Ce++ YAG is so bright that it will almost burn your retinas when one drags the beam across it in an electron probe with visual light optics. The usual material used to observe a beam itself is benitoite. Bright to most, but dim by comparison.

avatar Re: Andradite (y)?
February 27, 2012 04:06AM
I wasn't looking at the label while typing it in this AM as I was in a hurry. It is Ojos Españoles
avatar Re: Andradite (y)?
February 27, 2012 04:24AM
Thanks for the replies though

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