Garnets are a fascinating species of gemstones that have legends that predate the actual gemological definition of a garnet. One legend whispers from the secret passages of time of a magical gem that glowed with its own fire–a crystallized soul that was the ultimate guiding light in the darkest of times.
This carbuncle, as it was called, was said to have been used by Noah while he was on the ark. It glowed with a fiery red light when there was no sun, nor moon. Carbuncle stems from the Latin word, carbunculus which means small, hot coal. For Noah, this gem shone, “more brilliant by night than by day,” the story goes. Whether the gem was a garnet or a carbuncle or some ancient alien technology isn’t known.
Another legend tells us that Hunza warriors from Kashmir would use garnet gemstones in their weaponry. Garnet, due to its luscious red color was often associated with blood. The warriors would use these gems as pellets for their bows and then later on in time, as bullets for their guns. It was said that when one was struck by a garnet gem, the injury would be bloodier than normal.
The stories surrounding this gorgeous gem are older than its actual definition—and some carbuncles turned out to be rubies instead of garnets. However, it wasn’t until more modern times that Garnet gems were discovered in more than those deep fiery colors. Garnet is what is known as a species–not one single mineral but a group of several closely related minerals that have similar physical properties and crystal forms yet each has a unique chemical composition.
A general formula was assigned to this group: X2Y3(SiO4)3. The X represents calcium, iron, or manganese and the Y represents aluminum, iron or chromium. For example, Tsavorite’s chemical formula is Ca₃Al₂Si₃O₁₂, which shows it has calcium and aluminum in the mix. This specific mineral gets it color from the varying amounts of either vanadium or chromium. Due to the varying nature of the chemical composition of garnets, some garnets are stronger than others. Almandine is harder than Uvarovite which is something I learned the hard way when I first worked with Tsavorite–it’s more fragile.
Synthetic And Heat Treated Garnets
Before Cubic Zirconia was imitating diamonds beautifully, synthetic Garnets were the go to for simulated diamonds. Although they are still around, they are not so common anymore. There are three main types, that I know of so far, of synthetic garnets. GGG, YAG, and YIG.
Yttrium Aluminum Garnet (YAG) was a cubic yttrium aluminum oxide phase and in its pure state, has no uses as a laser medium. YAG is often used as a host material in various solid-state lasers today but was once used in jewelry. In jewelry, colored YAG gems were faceted and have a variety of trade names such as alexite, amamite, diamonite, Linde simulated diamond, and yttrium garnet–just to name a few.
Gadolinium gallium garnet (GGG), unlike YAG, has a high dispersion. The metals in these gems are more expensive than yttrium and have a dispersion close to that of a diamond. While GGG is also used in gemstone jewelry as a diamond simulant, it can also be used as a seed substrate for the growth of other garnets such as yttrium iron garnet, (YIG).
YIG is also known as yttrium ferrite garnet or iron yttrium oxide or yttrium iron oxide–the last two are often associated with their powdered forms. This mineral is used in microwave, acoustic, optical, and magneto-optical applications. As far as I can tell, it’s not really used in jewelry, but I thought it should be included in this post.
Proteus was a Greek god who shape-shifted. His name represents one who changes their appearance or principles. Few almandine-pyrope gems form us will change into Proteus–all other types resist change. It looks a lot like hematite in reflected light—in transmitted light the dark red shows thru.
Personally, I’ve never worked with any heat treated or synthetic garnets, but it’s definitely on my gem bucket list.