The difference between Garnet types

pauls Thanks for posting this. I'd already seen and bookmarked her garnet illustration. Garnets, along with the feldspars, are two of the most complex minerals used for gems and the feldspar group illustration is a welcome addition to my collection.

Garnets have been a special interest of mine for years. Differentiating garnet species in cut gems is difficult since there's so much intermixing (miscibility) between species and duplication of colors. If it's of interest to you, Dr. William A. Hanneman published a book some years back called "Naming Gem Garnets." It came with a fold-up "pyramid" called the "Rosetta Stone of Garnets" that lists garnet species by color and RI. I've found it immensely helpful. Unfortunately the book is out of print, I think, but a used bookseller may have a copy.

That blue color is spectacular!

This is my kind of thread!

Do you happen to know if the blue garnet is the one that is most often called the "color change garnet"? I can't remember.

rockjunquie Forgot I had this image: they're difficult to shoot becuse 2 light temperatures are needed to show the change. This is just a little guy, under 1 carat s I recall.

I have quite a few with strong color change. What many people don't understand is that the pure colors don't appear in mixed lighting or in some in-between light temperatures. The standard is daylight or incandescent, just like the alexandrites that were dubbed "daylight emeralds, nighttime rubies" before electric lighting was invented and night viewing was by candlelight. Today "warm" incandescent lights have about the same color as candles.

Here are a couple of my favorites. The cushion weighs 2.96 ct. and the trillion 1.66 ct.

Don't know about Doctorates but I've always wished I could have done a lot more searching for Idaho garnets. I've seen some gorgeous cut stones from other N. Idaho areas apart from Emerald Creek that have wonderful color, indicating mixing with other garnet species like Pyrope. The magnetism is due to the high iron content of Almandines.

Garnet color is fascinating to me. For instance, Almandine and Pyrope (with some major exceptions) are so dark-hued they cut almost black stones. But garnets love to mix species and when the two are mixed together they create the lovely intermediate species Rhodolite. And Rhodolite can contain other species like Spessartine, resulting in an awesome range of red-pink-purplish-orangish colors. Garnets have been vastly underrated gemstones.