Umbalite garnet whaaaa?

[historychick]

Hello all,
Sorry I''ve been away for a bit I was involved in a summer class that really whipped me. Three hours a night 4 nights a week....insane, but on to happier things which is why we are all here I was wondering what information you knowledgeable ladies (and gents) can share with me about Umbalite garnet I''m looking for anything b/c I know practically nothing of course pics are Always welcome.
Thanks.

 

[Elegant]

There have been some recent posts on this type of garnet...try a search and you will come up with some!

 

[Kismet]

I believe Umbalite refers to rhodolite garnets from the Umba region of Tanzania.

 

[Richard M.]

Date: 7/30/2008 8:35:40 AM
Author: Kismet
I believe Umbalite refers to rhodolite garnets from the Umba region of Tanzania.

Correct. And Rhodolite refers to an intermediate mixture of the pyrope and almandine garnet species. Because that mixture varies a lot in proportions, including minor amounts of other garnet species, there''s a huge range of advedrtised "rhodolite" colors.

An American dealer in rough gemstones claims to have named so-called Umbalite, which generally has a pinkish hue. He also named Raspberry Rhodolite. Both are color designations. Garnet trade names are notoriously unreliable and are very frequently misused. Sometimes they go in circles -- I just found an on-line ad for Umba garnets from Tanzania''s Tanga Province, LOL.

 

[historychick]

thanks for your replys

everyone so they are a specific type of rhodolite garnet? If I want more reliable info should I search for this term instead? Are garnet from the umba region more scarce than others? What kinds of charachteristics should I search for in a very good specimin of this stone? Sorry the quetions are so scatter brained. Thanks Richard for the technical info....

 

[Babyblue033]

My very first colored stone, and now on my beautiful ring, is a custom cut Umbalite Garnet. My stone is deep pink/purple color, which I think is one of their characteristics differing from other Rhodolite Garnets. It has a very special place in my heart

 

[Proteus]

Yes, it's a location-specific trade name for what is basically rhodolite garnet. Garnets form in a solid solution series, which is a technical term that I will try to explain: Basically, there are many different types of garnets, and they vary from chemical composition. These compositions can mix and overlap, which creates "hybrid" intermediate species. Rhodolite is a mixture of almandite and pyrope. That's why not all rhodolites will look the same - their physical properties vary somewhat based on the balance of almandite and pyrope. The particular variety of rhodolite from the Umba valley in Tanzania was named "umbalite" in the trade, but it's not really an official name. It is a fairly uncommon variety of rhodolite, but I wouldn't call it scarce. Like Richard mentioned above, dealers don't always get their names straight. Which makes things rather confusing and frustrating for the end buyer. The best thing to do is to be informed. In short, Umbalite should be a purplish-pink or fuchsia-colored variety of rhodolite, with a medium to medium-dark tone. I've noticed it tends to have a slight color shift (as do most garnets) depending on the light, and it may appear more pink or more purple. They are sometimes available in quite large sizes, and aren't horribly dark as some rhodolites may be. It's fairly common for it to have some silk inclusions. In my opinion, it is a very good variety of rhodolite.

If you want to get really technical, all garnets are separated into 2 types: pyralspite and ugrandite. Pyrope, almandite and spessartite belong to the pyralspite type and do not contain calcium. Ugrandite are calcium-containing garnets, and these are andradite (which includes demantoid), grossularite (which includes tsavorite), and uvarovite (which is very rarely used in jewelry.) The ugrandite garnets mix with eachother as do the pyralspite garnets, producing all sorts of subvarieties.