Almandine is perhaps the most common garnet species. Forming series with pyrope and spessartine garnets, these gems occur in the deep brownish or purplish reds most often associated with garnets. They make affordable and durable jewelry stones.
Almandine Garnet Value
Due to their abundance and occurrence worldwide, almandines generally fetch low prices. The purplish-red almandine-pyrope blend rhodolite is an exception. See our garnet buying guide for information on value factors for almandines and other garnets.
Almandines have a distinctive, diagnostic absorption spectrum: A band 200 ? wide at 5760 (strong) and also strong bands at 5260 and 5050. Lines may appear at 6170 and 4260. With a spectroscope, you’ll see this pattern of 3 (or sometimes 5) bands in all almandines as well as most garnets with a significant almandine component.
N = 1.75-1.83; usually above 1.78. May show anomalous birefringence.
A corruption of the name of a classic source of this garnet, Alabanda, in Asia Minor,? now Turkey.
Almandine is a widespread constituent of metamorphic rocks; also in igneous rocks, in contact metamorphic zones, and as an alluvial mineral.
See “Identifying Characteristics” below.
Almandine (garnet): Idaho (1.0), Africa (4.5, 9.0), Brazil (24.2), Africa, rhodolite (8.0, 3.5). Photo ? Joel E. Arem, PhD, FGA. Used with permission.
Like all garnets, iron-dominant (Fe) almandine virtually always occurs in series with other garnet species. Most frequently, with magnesium-dominant (Mg) pyrope, it forms the deep red garnets often encountered in commercial jewelry. With manganese-dominant (Mn) spessartine, it forms more brownish to orangish red garnets. Almandines can also show purplish red, wine red, and purple colors.
Known also as almandite (chiefly a British usage), almandine has been popular throughout history. The Ancient Egyptians used almandines in jewelry as early as 3,500 BCE. The Classical Roman scholar Pliny the Elder called the finest red gemstones with “brilliancy like fire” carbunculus, a grouping which included almandines and likely red spinels and rubies as well. Although no longer used professionally by gemologists, the term “carbuncle” persisted into the 19th century and came to refer to cabochon-cut red gems, most commonly almandine garnets. You might still encounter this term in descriptions of antique jewelry.
As an affordable garnet species, almandines make an excellent choice for January birthstone jewelry.
Almandine Garnet Varieties
Rare star garnets come primarily from India and the U.S. state of Idaho. (The star garnet is the Idaho state gem). When properly cabbed, almandines with inclusions of asbestiform minerals (pyroxene or amphibole) may yield a 4 or 6-ray asterism effect. The Idaho material has a refractive index(N) of 1.808 and a specific gravity (SG) of 4.07. (Due to inclusions, the SG can reach up to 4.76).
A band 200 ? wide at 5760 (strong) and also strong bands at 5260 and 5050.
Lines may appear at 6170 and 4260.
With a spectroscope, you’ll see this pattern of 3 (or sometimes 5) bands in all almandines as well as most garnets with a significant almandine component.
A deep burgundy almandine-spessartine garnet on a white matrix. 6.4 x 6.3 x 6.1 cm, Ialamitana, Sahanivotry Commune, Antsirabe 2 District, Vakinankaratra Region, Antananarivo Province, Madagascar. ? Rob Lavinsky, www.iRocks.com. Used with permission.
Geologists have manufactured via the hydrothermal method pure synthetic almandine crystals as well as almandine-pyrope blends. Synthetic almandines have appeared on the gem market. A gemologist should look for telltale signs of hydrothermal growth, including seed plates.
For other synthetic garnet varieties, consult the “Synthetics” section of the main garnet gem listing.
Very large crystals exist, but due to the material’s dark tone, gem cutters usually facet only small to medium-size gems. If cut shallow, these let light pass through. The condition of the rough also limits finished sizes. For example, the Barton Mine in New York has produced 60 cm crystals in rock.?However, this material is so badly shattered that stones only up to 2 carats can be cut from the fragments.
Indian and Brazilian almandines constitute the bulk of material on the marketplace.
With no cleavage and a hardness of 7-7.5, almandines make durable stones for any type of jewelry setting. (For gem design ideas, see Jeff Graham’s article for recommendations). However, exercise care when cleaning. Almandine’s microscopic inclusions may burst due to extreme heat or ultrasound, fracturing the gem. Avoid these mechanical cleaning systems and stick to?a soft brush, mild detergent, and warm water, instead.