Difference between revisions of "Gadolinium gallium garnet"

Latest revision as of 11:13, 4 January 2023

Gadolinium gallium garnet, Gemological Institute of America

Description

A colorless synthetic crystal of the garnet group that has been used as an imitation diamond. Gadolinium gallium garnet (GGG) stones were produced for a short time in the 1970s when the production of yttrium aluminum garnet (YAG) dropped. The GGG stone had a refractive index and dispersion nearly identical to diamonds. They were also hard enough to maintain clean faceted edges. However, their ingredients were much more expensive than YAGs and they had the unfortunate tendency to turn dark brown when exposed to sunlight. Additionally, their density was the highest of all imitation diamonds.

Synonyms and Related Terms

Raman spectrum of gadolinium gallium garnet; RRUFF

GGG; Diamonique II; Galliant

Physical and Chemical Properties

Luster = vitreous to subadamantine
Pleochroism = none
Fluorescence = moderate to strong pinkish orange in SW; inert to moderate orange in LW
Birefringence = none

Mohs Hardness	6.5 - 7.5
Density	7.08 g/ml
Refractive Index	1.970
Dispersion	0.045 (moderate fire)

Comparisons

Properties of Natural and Simulated Diamonds

Resources and Citations=

Gem Identification Lab Manual, Gemological Institute of America, 2016.
Wikipedia: [1] (Accessed Dec 2022)

@@ Line 1: / Line 1: @@
-[[File:CZ_brilliant.jpg|thumb|Cubic zirconia]]
+[[File:Gadoliniumgalliumgarnet X090005 Sample Photo 24558 M.jpg|thumb|Gadolinium gallium garnet, Gemological Institute of America]]
 == Description ==
-A colorless synthetic crystal of the garnet group that has been used as an imitation diamond. Gadolinium gallium garnet (GGG) stones are us. Cubic zirconia (CZ) are very hard and have a high refractive index. It is composed of a single crystal of synthetically prepared [[zirconium oxide]].  During manufacture, calcium or yttrium are added as a metal oxide stabilizer, which allows the growth of the single crystal.  The technique was first researched in France in the 1960s, then perfected in Russia in 1973 at the Lebedev Physical Institute. Commercial imitation diamonds have been on the market since 1976.  Some coatings have been applied in recent years that make the stone visually indistinguishable from diamonds.  The variations between the two stones are: 1) CZ are flawless, unlike natural diamonds, and 2) CZ has a lower thermal conductivity, higher dispersion, higher specific gravity, and often a poorer faceted cut.
+A colorless synthetic crystal of the garnet group that has been used as an imitation diamond. Gadolinium gallium garnet (GGG) stones were produced for a short time in the 1970s when the production of [[Yttrium aluminum garnet (YAG)|yttrium aluminum garnet]] (YAG) dropped. The GGG stone had a refractive index and dispersion nearly identical to diamonds.  They were also hard enough to maintain clean faceted edges.  However, their ingredients were much more expensive than YAGs and they had the unfortunate tendency to turn dark brown when exposed to sunlight.  Additionally, their density was the highest of all imitation diamonds.
 == Synonyms and Related Terms ==
+[[File:GGG Raman RRUFF X090005.png|thumb|Raman spectrum of gadolinium gallium garnet; [https://rruff.info/gadolinium/display=default/X090005 RRUFF]]]
+GGG; Diamonique II; Galliant
-GGG
-[[File:Cubic zirconia Raman RRUFF R040142.png|thumb| Raman spectrum of synthetic cubic zirconia; [https://rruff.info/cubic%20zirconia/display=default/R040142 RRUFF]]]
 ==Physical and Chemical Properties==
@@ Line 38: / Line 38: @@
 * Wikipedia: [https://en.wikipedia.org/wiki/Gadolinium_gallium_garnet] (Accessed Dec 2022)
+[[Category:Materials database]]
- Gadolinium_gallium_garnet[[Category:Materials database]]