Garnets For Sale

Garnets are not a single mineral but a term used to describe a group of closely related minerals. Garnets come in a variety of colors from red, to green, yellow, black, pink, and orange. There are many different varieties, but the most important are almandine, spessartine, pyrope, uvarovite, grossular and andradite. They are some of the hardest minerals on the planet and are commonly used as both abrasives and as gemstones. Garnets have always made attractive gemstones and have their own respectable corner in the gem trade. Collectors shouldn’t overlook raw garnet associations, since they make phenomenal display pieces and have significant aesthetic appeal.

Smoky Quartz Cluster Encrusted With Garnets - Wow! #51036

6.5" Smoky Quartz Cluster Encrusted With Garnets - Wow!

SOLD

Plate Of Over Twenty Red Embers Garnets - Spectacular #111839

7.2" Plate Of Over Twenty Red Embers Garnets - Spectacular

SOLD

Lustrous, Rich-Green Demantoid Garnets - Iran #280742

2" Lustrous, Rich-Green Demantoid Garnets - Iran

SOLD

Dark Smoky Quartz Crystals with Spessartine Garnets #51035

3.8" Dark Smoky Quartz Crystals with Spessartine Garnets

SOLD

Smoky Quartz Crystal Covered In Garnets #44793

2.8" Smoky Quartz Crystal Covered In Garnets

SOLD

What Are Garnets?

Garnets are nesosilicates that share a general formula of X3Y2(SiO4)3. There are six primary species of garnet: include pyrope, almandine, spessartine, uvarovite, andradite, and grossular (which encompasses the ever-popular tsavorite). Garnets are found in a wide variety of colors including red, orange, yellow, green, purple, brown, blue, black, pink, and colorless, though shades of red are the most common. All six species of garnet are extremely closely related, and many intermediaries exist between them. Some species are so similar that X-ray analysis is the only means of distinguishing one from another.

The garnet group all share an isometric crystal structure and most will appear as dodecahedral crystals. This twelve-sided shape is most often exhibited by garnets, though other minerals do form in this fashion. However, garnets and dodecahedral crystals are almost synonymous. The garnet group also forms in trapezohedral, grainy, rounded, and massive crystals.

Garnets are very hard, scoring somewhere between 6 and 8 out of a possible 10 on the Mohs Hardness Scale. This hardness is beneficial when it comes to cutting and faceting minerals into gems. Their intrinsic beauty and ability to be easily cut have also made them a wildly popular gemstone throughout history. Raw, natural associations of garnet make excellent display pieces and are becoming a prized collector item. Within the last century, garnet has become increasingly useful in industry. Its hardness makes it an excellent abrasive, used primarily for waterjet cutting and abrasive blasting in manufacturing. Garnet's high specific gravity and slightly porous nature also make it an effective filtering material to remove contaminants from solutions.

Important Species

The garnet group comprises six major species that can be split into two subgroups. The first of these subgroups contains aluminum as the second element in their chemical composition. Spessartine, almandine, and pyrope garnets make up this lot. The second subgroup is characterized by the inclusion of calcium as their first element. These are uvarovite, andradite, and grossular garnets.

How Do Garnets Form?

Garnets form in any geologic environment, whether igneous, sedimentary or metamorphic. Some species are more likely to form in specific environments than others. Garnets are considered an accessory mineral to certain igneous rocks (e.g. granite and basalt) and are thus often found in pegmatites that form these rocks. Because garnets are very durable, they often end up in sedimentary deposits where rocks containing these minerals have weathered and were relocated before settling. Miners prefer to extract garnets from sedimentary material because it is significantly easier to collect than removing the embedded minerals from metamorphosed rock. Metamorphic environments seem to produce the largest amount of garnets, but the specific type of metamorphism differs between the aluminum (pyrope, almandine, spessartine) garnets and the calcium (grossular, uvarovite, andradite) garnets. Aluminum garnets form best in areas of regional metamorphism where heat and pressure melt and recrystallize minerals into a new stable form that layers upon itself over time. This is why so many of the aluminum garnets are opaque and full of impurities. Calcium garnets will typically form at locations where contact metamorphism happens. This usually occurs along igneous intrusions where large deposits of limestone are altered. It is for this reason that the calcium garnets are often on the softer side of the garnet spectrum. Skarns are another location where granites are prolific. These geologic occurrences are a result of super-hot liquids flowing through existing rock and recrystallizing present minerals. This process is called metasomatism and can be thought of as a fluid version of regional metamorphism.

Where Is Garnet Found?

Garnets are found worldwide, though some regions produce specific species in greater abundance and quality than others. See the specific garnet species above for further information on location.

Pyrope - This species of garnet is closely related to almandine and the two look very similar, though pyrope is significantly more rare. The key to telling them apart is that pyrope is often very transparent, lacking flaws or impurities. These characteristics, in addition to its deep red coloring, make it an exceptional gemstone. Pyrope typically forms in igneous kimberlite pipes in close association with diamonds. These crystals often present as individual, misshapen, dodecahedral crystals embedded within their deposit. Pyrope is found in a few small deposits throughout the world. Northern Europe (Norway, Scotland, Italy, Switzerland and Czech Republic) has produced excellent gem-quality pyrope specimens. Tanzania and some South African diamond mines have been known to produce impressive pyrope garnets as well. The US and Canada are also home to small but significant pyrope deposits.

Spessartine - This garnet forms a series with almandine and it is nearly impossible to tell the two apart when they occur in the same locations. Spessartine is often a bright orange or red-orange in color and is the go-to for orange garnet jewelry. This mineral occurs as singular trapezohedral crystals in granite pegmatites and in areas of contact metamorphism. Spessartine was once very rare, but recent finds in Tanzania have put the garnet back on the map. These garnets are now very popular collector items. Spessartine can also be found in China, Pakistan, and Brazil among a few other smaller localities.

Almandine - Among the multitudinous variety of garnets, almandine stands above the rest as the most common and most popular. More almandine garnets are cut into gemstones than any other species, which is surprising because most almandine is opaque and nowhere near gem quality in transparency. These garnets are often very dark red in color with balck edging, or may even be solid black. These dodecahedral crystals are easily confused with pyrope garnets, though the latter is much less transparent and forms in aggregations that are deeply embedded in the surrounding rock. This variety forms in all three geologic environments, specifically igneous pegmatites, areas of regional metamorphism, and alluvial sedimentary deposits. Almandine is the garnet most often used as an abrasive in industrial manufacturing. Because these garnets are so common, they are found worldwide. The most significant occurrences are in northern Europe, specifically Austria and the Czech Republic. Almandine is also abundant in the United States; Alaska produces world-famous specimens.

Grossular - Grossular garnets are one of the only garnets that form in only metamorphic environments, along with uvarovite. This garnet species is easily the most colorful, appearing in every color except for blue. Tsavorite (emerald green) and hessonite (brown-orange) are two grossular garnets that are extremely popular in the gem trade, especially tsavorite, which passes for a cheaper emerald substitute. Andradite and grossular garnets form a series with many intermediaries between the two. A popular example is the Mali garnet, which can belong to either species and can only be determined via X-ray analysis. Grossular crystals will form as individual, or aggregations of, dodecahedral crystals with sharp terminations. These garnets occur worldwide, but certain localities produce some “subspecies” where others do not. Italy produces excellent hessonite specimens, while Kenya mines superb tsavorites, and the two species don’t typically overlap. The highest quality grossular garnets come from Quebec, Canada, and are quite astonishing to behold. Many of these occurrences are in close association with the mineral diopside.

Uvarovite - This species of garnet is the only species that is explicitly green in all its forms. It is also the only garnet that contains chromium as a major element of its composition. It is this chromium content gives this species its characteristic emerald-green colors. Another major indicator of uvarovite is its tendency to form lustrous druzy aggregations of dodecahedral crystals that thickly coat its matrix. Uvarovite only forms in chromium-rich metamorphic environments, which explains why this mineral often occurs in serpentine deposits in Russia and Finland. Because of its specific formation conditions, uvarovite is fairly rare in nature: only three major localities (Finland, Italy, and Russia) produce quality specimens.

Andradite - Andradite crystals appear in a variety of forms but are typically dodecahedral or massive, or occasionally grainy. These crystals fall within a range of colors from opaque black to sparkly yellow and translucent green. This species of garnet is particularly known for the extreme luster of its group members. They are fairly rare, but are considered some of the most attractive specimens by mineral collectors. Andradite garnets will form in any environment but are most often found in igneous basalt and granite pegmatites, metamorphosed limestones, and aquatic sedimentary placer deposits. Demantoid garnets are one of the most popular andradite varieties and make exceptional gemstones. Despite its rarity, andradite garnets occur worldwide with significant deposits in multiple countries. Russia, Canada, Italy, Namibia, and Pakistan mine some of the finest demantoids on the market, with specimens that are sure to please. Premium melanites and topazolites come from Mexico and California, and Italy is making a splash in the topazolite market as well.

Common Associations

Because of its wide family tree, garnet has many common associations between the plethora of species. Despite this diversity, some associations appear alongside most garnet species. Quartz, calcite, and biotite most often make an appearance with almost all garnet species, but associates really depend on species and formation location. For instance, pyrope may be found with diamonds, while spessartine occurs with muscovite and uvarovite associates with diopside, but these associations do not usually overlap between the species.

What Are Garnets?

Important Species

How Do Garnets Form?

Where Is Garnet Found?

Common Associations