garnets

[lavatea]

Can someone educate me on garnets? Or point me somewhere with good information?

There are so many garnet terms and I'm confused: tsavorite, almandine, mali, rhodolite, etc, etc.

Thanks!

 

[movie zombie]

go to pala.com and read all about them. garnet is a "family" with many species within it....all dependent upon chemical composition as to which label anyone of them gets. have fun! this is a wonderful "famiily" to buy into!

MoZo

 

[Largosmom]

I am one or two steps ahead of you. As you have already learned, garnets are complex. The names are from color and from the minerals and metals that make up the stones. Garnets can have mixes that make them difficult to put cleanly in one category or another. I have a couple of books, but only one handy at the moment. I will try to summarize from the Smithsonian book "Rock and Gem", which I got off the shelf at a local bookshop.

Garnets are a group of crystal forming minerals with quite a few possible combinations of minerals that define them. Their crystal shapes may be different, but I will let you look that information up. The book notes that garnet often forms good crystals. Rocks and gems are classified by color, crystal shape, and mineral content (oversimplifying), and sometimes by where they are found and in what type of rock found.

Types of Garnet are:

Pyrope
Colors: dark red, violet red, rose red, reddish orange
Found as rounded grains or pebbles

Spessartine
Colors: pale yellow through orange to red and shades between.
Found in manganese rich types of rock.
Pure spess is rare. It is often mixed with almandine.

Malaya garnet is a mix of spess and pyrope

Almandine
Colors: tends to be pinker than other garnets.
Found in several types of rock and can be an inclusion in a diamond.
Most common type of garnet and also used as an abrasive

Andradite
Colors: yellowish, yellowish green, emerald green, brownish red, brownish yellow, and grayish green
Found often with grossularite garnet. Andradite has strong dispersion like diamonds.

Demantoid garnet is andradite garnet in greens and yellowish green with chromium.

Grossular
Colors: colorless, pink, cream, orange, red, honey, brown or black.

Hessonite is a reddish-brown variety of grossular garnet

Tsavorite is green grossular garnet.

Uvarovite
Color: green
Usually too small to be cut. Color comes from chromium. Rarest of gem garnets.

I did not find Mali or rhodolites in this book.

 

[T L]

I did not find Mali or rhodolites in this book.

Mali and rhodolite are marketing names. Mali is a yellow or greenish-yellow grossular and rhodolite is a pink variety of pyrope/almandite.

 

[movie zombie]

re mali: http://www.gemsociety.org/info/gems/mali.htm

more than a marketing name; also a point of origen.

actually, go to their website and see what they say about all the garnets.

MoZo

 

[lavatea]

Thanks everyone! I will be checking out the links tomorrow with my morning coffee.

 

[chrono]

Umbalite is also an origin name for rhodolite garnet.

 

[T L]

Yes, Umbalite refers to rhodolites from the Umba valley in Tanzania.

 

[Lady_Disdain]

One of the fascinating but confusing things about garnets is that the categories aren´t exclusive. A particular stone can be, for example, 60% pyrope and 40% spess, considering its chemical composition. This leads to all sorts of shades and can affect other characteristics, such as RI.

 

[Largosmom]

I am enjoying the Smithsonian book while traveling. It starts with how planets form and works you into different types of rocks are formed. It is like a mini geology refresher if you enjoyed that in science class. I haven't gotten to the gemstones yet but am looking forward to it after a mini read in the garnet section last night

So it seems that garnets are like those recipes that cooks like to mess with...chili, salsa, etc.,that have some common types of ingredients but each cook makes his or hs a little bit different, and when you mix in something special you get a little more zing or a different color going on. I guess that makes andradite the hot peppers of the garnet world. More andradite in the mix gives more fire!

 

[movie zombie]

So it seems that garnets are like those recipes that cooks like to mess with...chili, salsa, etc.,that have some common types of ingredients but each cook makes his or hs a little bit different, and when you mix in something special you get a little more zing or a different color going on. I guess that makes andradite the hot peppers of the garnet world. More andradite in the mix gives more fire!

love it!

MoZo

 

[Largosmom]

Researching this thread made me discover that there is a famous site for spess garnet about 2.5 hours from where I live! Amelia Courthouse VA had a mine called the Rutherford that is known for orange spessartite. I guess this was decades ago, but it's kinda cool to know that there are gemstones from near where you live.

Laura

 

[PrecisionGem]

I did not find Mali or rhodolites in this book.

Mali and rhodolite are marketing names. Mali is a yellow or greenish-yellow grossular and rhodolite is a pink variety of pyrope/almandite.

]

TL, that's not really true. A Mali garnet is a mix of grossular and andradite. It has more dispersion than a grossular garnet. I think the only known source of Mali garnets is Mali in West Africa. A well cut Mali will almost look like a diamond.

 

[T L]

Thanks for the correction Gene. I apologize.