Mali Garnet (also known as “Malaya Garnet”)
Mali Garnet Information
CHEMISTRY Calcium, iron/aluminum silicate, (varies with composition)
REFRACTIVE INDEX 1.760 – 1.780
SPECIFIC GRAVITY 3.49 – 3.85
HEAT SENSITIVE No
DISPERSION .028 – .057
WEARABILITY* Very Good
SPECIAL CARE INSTRUCTIONS None
ENHANCEMENTS None known
*Wearability is graded as Excellent, Very Good, Good, Poor, and Forget It! For more details see the article on “Hardness and Wearability.”
Mali Garnet, one of the rarer varieties within the garnet group, is a mixture of the species grossular and andradite, (therefore it is sometimes called “grandite.”) The entire garnet group is a solid solution series of silicates. That means the crystal structure is basically the same throughout the group, but some of the chemical formulas differ. At certain key points throughout the series, designated species names are given, such as pyrope, almandite, spessartite, grossular, etc. These species exhibit different optical and physical properties due to their differing chemistries. Each is a silicate of aluminum, chromium, or iron combined with magnesium, manganese, iron, or calcium.
A nearly infinite array of named and as yet unnamed, varieties of garnet exist in Nature. Two varieties that have come to recent popularity are rhodolite and malaya. They are hybrids: rhodolite garnet consists of almandine and pyrope; malaya garnet is a mixture of pyrope, almandine, spessartite and grossular.
In terms of Mali’s own relatives, tsavorite and hessonite are two well known color varieties of grossular and demantoid is a variety of the rare andradite.
Representatives of the parent species of Mali garnet: hessonite garnet (grossular), demantoid garnet (andradite)
The name, Mali, is based on the country where the specimens are mined in West Africa. It was discovered in 1994 and Mali is still the only known source. This previously unknown gem is brilliant, highly dispersive, yellow to yellow-green, or brown. Gemological study has proven that the new gem’s composition is intermediate between that of grossular, (calcium aluminum silicate,) and andradite, (calcium iron silicate.) Although Mali garnets are predominantly grossularite, the variable admixture of andradite changes its characteristics in at least one important way. The hybrid, Mali, seems to favor its grossular parent in terms of refractive index, (1.77 in most specimens,) and hardness, but derives its superb dispersion from its andradite heritage.
Most rough is mined from alluvial deposits and shows the rounded, water worn shape typical of that source. A great deal of material was produced the year following its discovery. The popularity of this pretty stone soared and prices were initially very high, but soon began to drop off. In recent years, much smaller amounts have been produced which has resulted in an increase in price. As large size rough is rare in this variety, price per carat increases dramatically with size.
Colors range from yellow, to greenish yellow, to yellowish brown, to brown. Cut stones are remarkable for their brilliance and most notably their dispersion when the body color is light enough to let it show. As with all garnets, no special care is necessary in setting or wearing and they are suitable for all jewelry uses. No enhancements or synthetics are known in the market.
No doubt the high end of this variety’s value range is reserved for the extremely rare chrome green color. In general yellow, yellow green and green yellow stones go for higher prices than the brownish stones. As with any gem, size, clarity and cut affect the value dramatically, with dispersion being a special value factor for Mali garnets.
Barbara Smigel at Artistic Colored Stones.
Dr. Joel Arem, who has generously allowed us to utilize some content from his encyclopedia.