shape
carat
color
clarity

Orange Grossular Garnet

Status
Not open for further replies. Please create a new topic or request for this thread to be opened.

librarychickie

Shiny_Rock
Joined
Jan 25, 2008
Messages
452
Can someone tell me exactly what it is? I have found one that I really like the color and cut of; however, what makes it different from a Spessartite?

Thanks for the input!

~LC
 

ma re

Ideal_Rock
Joined
Aug 10, 2008
Messages
2,698
Chemistry. Spessartite is one of the aluminium group garnets and grossular is from the calcium group garnets. Not that I know so, but I googled it out in like 2 minutes
9.gif
Details are available at: http://www.palagems.com/spessartite_buyers_guide.htm
 

Richard M.

Brilliant_Rock
Trade
Joined
Feb 17, 2004
Messages
1,104
Date: 2/23/2009 9:19:15 AM
Author:librarychickie
Can someone tell me exactly what it is? I have found one that I really like the color and cut of; however, what makes it different from a Spessartite?


Thanks for the input!


~LC
Hi,
Grossular and spessartite garnets are different species. Both are aluminum silicates. Grossular is a calcium garnet and spessartite is a magnesium garnet. Both are members of the garnet group and while they crystallize in the same form (cubic) each species has different physical properties. There are some 20 known garnet species but only 5 of them (if you don''t count cross-species mixtures like "rhodolite" and "malaia") are used as gems. Green uvarovite druses are currently being cut for gem use so maybe we could say 6 species are used.

Grossular garnets have the widest color range of any gem garnets. Grossular is the only garnet species that occurs pure or near-pure outside the laboratory, so colorless or near-colorless grossulars are known. The species gives us tsavorite, mint garnet as well as orange-brown hessonite and many other hues: yellow, orange, orange-red, peach, pink in many shades. The pale green color of some grossulars reminded people of gooseberries, so that''s how the species got its name (Latin ''grossularia'').

Spessartites and grossulars differ in brilliance. Spessartite has a refractive index of 1.79 to 1.81, making it among the most brilliant of orange gems; grossular has an R.I. of 1.73 to 1.76. There are other differences in density and typical inclusions.
Richard M.
 

Catmom

Super_Ideal_Rock
Premium
Joined
Apr 6, 2005
Messages
12,414
Thank you so much Richard! That was very interesting and something I didn''t know about garnets.
 

Richard M.

Brilliant_Rock
Trade
Joined
Feb 17, 2004
Messages
1,104
I can''t figure out how to edit posts but I made a mistake above. Spessartite is a manganese, not magnesium garnet. My coffee-deprived brain got the two mixed up.
Richard M.
 

librarychickie

Shiny_Rock
Joined
Jan 25, 2008
Messages
452
Thanks for information!
 
Status
Not open for further replies. Please create a new topic or request for this thread to be opened.
Be a part of the community Get 3 HCA Results
Top