Monday, September 20, 2010

Garnets (just a taste!)

I've been told by locals this is one of the finest Garnets gotten out of the top few inches of sand on this river beach.  Of course it has yet to be cut and polished.  These loose garnets have come a long way down the mountain, and I have yet to make the trek upward.  I have been told bigger ones are at a higher elevation, but that will wait for my next trip.  I literally collected all the garnets you see on this page either on top of the ground or within a few inches underneath.  The loose garnets in the picture were found the way you see them.  I am told that the whitish or cream coloration you see on the outside of most of these specimens is calcite.  I need to confirm that, though.

After tumbling down the mountain side and breaking out of the host rock from erosion or from the impact of other boulders, most of these garnets do have stress fractures.  A few of them look as though they may become decent gemstones. The top row of bigger "rocks" are garnets still stuck in matrix.  The rest are loose and need to be cleaned & polished.  Like I said, though, there are probably only a small percentage of them that will make nice gemstones, unless of course they are star garnets.

Like I said, I do not have my testing equipment yet, but as of yet I will say that the majority of these garnets appear to be Almandine Garnets (also known as Almandite).

Garnets in Granite and Mica Schist boulder!

Gemstones are classified by Group, then Species within a group, then varieties of a species.  Garnets can be quite complicated.  For instance, Rhodolite garnet is a "transition" garnet between Almandine garnet and Pyrope garnet.  In case I've already started to lose you, here is a list of garnets in the garnet group:

Almandine: Dark red
Rhodolite (Almandine/Pyrope): Purplish red
Pyrope: Medium red
Malaya (Pyrope/Spessartite): Blue, green, & color change
Spessartite: Orangy red
Grossularite: Varies in color
Andradite: Green
Uvarorite: Green

Although some garnets may be the same color, the chemical composition and inclusions may vary slightly, thus creating a different species or "transitional" variety.  Feel free to ask questions about this.  There are many books and websites that explain the Garnet Universe in it's entirety.  
Spessartite Garnet (I'm pretty positive) - notice the different host rock or matrix?  This actually came from about 50 miles away from the above garnets.

Where I am prospecting many people not only mistake garnets for rubies, but even insist a ruby is a dark super transparent red garnet and everything else is, well, a garnet.  So many amateur prospectors and gem collectors believe this here, that I feel it important to say this.  A Ruby is actually a red stone belonging to the Corundum group.  The Corundum group consists of Rubies (red corundum) and Sapphires (every other color of corundum).  Rubies and Sapphires are not Garnets, and Garnets are not Corundum.