Naming Gems

Similarly to the way organisms are named in biology, in gemology, each distinct type of gem has a species name.

Species: A gem species is a mineral that has a definite chemical formula, and has a particular three dimensional structure. In regards to that structure, gems can have a crystalline (highly regular and organized), or amorphous (less organized) structure.

An example of a gem species is quartz. All quartzes, whatever their other characteristics, share the same chemical formula: SiO₂ and are members of the hexagonal crystal system. (We'll be looking at the characteristics of the various crystal systems in a later lesson). The species "quartz" encompasses many quite different looking gems, though, from amethyst and citrine, to agate and jasper, to rutilated quartz and tiger'seye.

Another example of a gem species is corundum (commonly known as sapphire). All corundum gems share the chemical formula: Al₂O₃ and are members of the trigonal crystal system. 

Variety: A gem variety is composed of a sub-group, within the species, that shares distinct and notable characteristics, such as color, degree of transparency, inclusions, or optical phenomena with others of its kind. Not every gem species has multiple varieties, for example, there are no separate varieties within the gem species peridot.

Quartz Gems: 

[Species quartz: Varieties: amethyst, agate]

Amethyst is transparent, crystalline, purple quartz. Agate is translucent, usually banded or patterned, cryptocrystalline (made of ultra-microscopic crystals in an aggregate) quartz. Amethysts come in a range of purple colors from very light to dark, and agates come in a nearly infinite array of colors and patterns.

Corundum Gems: 

[Species corundum: Varieties: ruby, yellow sapphire, star sapphire]

Ruby is the variety name for red corundum, yellow sapphire is yellow corundum and star sapphire is translucent to opaque corundum that shows the optical phenomenon of asterism (forms a star figure from reflected light). The only variety of corundum that is simply called "sapphire" without any modifier is blue sapphire, all other colors have their own variety name (like ruby) or use a modifier like star, yellow, pink, white, etc.

Groups: In some cases, a number of closely related mineral species are placed into a larger, more inclusive category, called a mineral group. Examples are the garnet group and the feldspar group.

The individual species of the group share membership in the same crystal system, but although the chemical formulas amongst group members are very similar, they are not exactly the same throughout the group. Typically, the formulas gradually change by substitution of a set of chemical elements from one end of a continuum to the other.

Garnet Group: All garnets, whatever their individual species and varietal designations, are members of the isometric crystal system and are metallic silicate minerals with various proportions of Ca, Fe, Mg, Al, Cr and Mn substituting for each other within a similar chemical formula.

(To amplify: the generic formula for any garnet is A ₃B ₂Si ₃O₁₂ where the "A" position can be occupied by iron, calcium, manganese or magnesium, and the "B" position can be occupied by aluminum, iron, titanium or chromium. The rest of the formula is standard for all gems known as garnets).

Garnet Group Gems:

[Group: garnet, Species: Spessartite锰铝磂石, Group: garnet, Species: grossularite钙铝榴石, variety: Tsavorite]

The orange oval stone above belongs to the Spessartite* species within the garnet group. (Spessartites are manganese rich), and no individual varieties are designated within this species. The green stones above belong to the calcium rich grossularite species within the garnet group. There are several named varieties of grossularites, including medium to dark green stones colored by trace amounts of chromium and vanadium, called Tsavorite. * 

*When species or variety names come from proper nouns such as those designating a person (like Kunzite, named for G. F. Kunz, or Spessartite, named after the type location, Spessart in Germany), they are capitalized. Otherwise lower case is used, as in grossularite, agate and amethyst.

Trade Names and Misnomers误命名:

In addition to the official names given to gems, there are also a multitude of trade names, brand names, and misnomers that are in use. In fact, just as happened in the history of biology, the confusion over which mineral or gem was called what, where, by whom, has led to the development of a rigorous system for international naming of minerals and gems. Although this formal system is used by professionals, students, and serious gem enthusiasts among the public, many other names are still in use and can create confusion.

Trade Names:

In modern times, trade names have most often developed when a new gem material is first discovered and marketed, as a way to "romance the stone". Let's say you are in Tanzania and you mine a facetable, but insipid looking light brown, transparent form of the mineral zoisite. You discover that heat treating will turn it to a gorgeous blue-violet color. The correct descriptive term would be: heated brown zoisite.

Who would rush out to buy that? But, what if you call this gem something exotic and evocative of its foreign mine site, like "Tanzanite"--> now you something more marketable!

[Heated brown zoisite = Tanzanite]

Sometimes, what starts out as a trade name becomes so widely used that it is essentially adopted as the official name. Exactly this has happened in the case of Tanzanite.

Other examples of names which started out as marketing ploys策划 and ended up on the officially sanctioned list include: "Kunzite" for pink spodumene锂辉石, named for the famous early 20th century gem explorer and writer, G. F. Kunz and, "Tsavorite" for green grossular garnet named for its original mine locale (Tsavo National Park in Kenya).

[Kunzite, Tsavorite]

This strategy doesn't always work, and intended trade names sometimes fail. There are numerous examples in which trade names were used for a period of time, or by a specific seller, but then either died out, or never became widespread. An aggressive campaign to present heated blue zircon as "Starlite" failed, as did a similar effort to label high grade sugilite苏纪石 as "Royal Azel".

[Still just blue zircon and gem grade sugilite]

The jury is still out on some:

The relatively recent gem discovery, blue pectolite, which occurs only in the Dominican Republic in one location, has been promoted vigorously as "Larimar"--> named by the mine owner for a conjuction of his daughter's name and the local word for "sea". At this point the general consensus seems to be in favor of this lovely name.

Within the last few years a deposit of strikingly marked purple and white opalized fluorite has been sold as "Picasso Stone" among other creative trade names. Although you still see this and various other terms in use, most folks in the gem world seem to be sticking with the more mineralogically descriptive name, opalized fluorite.

[Blue pectolite or "Larimar"?, "Picasso stone" or opalized fluorite?--> not finally decided yet!]

Brand Names:

Brand names usually develop when a seller is trying to differentiate their product from other identical or very similar ones. A case in point--> each of the two major home shopping channels sells its own brand named version of the diamond simulant cubic zirconia. QVC sells it as "Diamonique^TM" and HSN as "Absolute^TM". Cubic zirconia, or CZ, is widely sold under its generic name at lower prices, so here, the name becomes a way of "branding" that creates "added value" in the marketplace. We are all quite familiar with this concept in the marketing of common food staples like catsup and mayonnaise, but it is every bit as effective a device in selling gems and jewelry.

[Absolute^TM, Diamonique^TM or plain old CZ?: depends on the seller]

Misnomers: 

A misnomer is a wrong, or false, name. Often misnomers are folk names, from ages past, that have persisted into modern times. Sometimes they are used out of ignorance, but sometimes, unfortunately, they are used to deceive.

[Misnomers: "smoky topaz", for smoky quartz, "white turquoise" for howlite硅硼钙石]

One of the few vintage 葡萄misnomers that can still occasionally be heard, even among modern day jewelers, and reputable gem dealers, is "smoky topaz". For many years this name was used incorrectly for the gem smoky quartz. Probably, it started out innocently enough, as many such names do, as a language translation failure, or an inability to correctly identify the species. Its use grew, however, even after the true identity was established, due primarily to the profit motive. Topaz is a generally more valuable gem than quartz, so by calling this variety of quartz by the topaz misnomer, it could sometimes be sold at higher prices to the unwary.

In their defense, individuals from earlier centuries who searched for, and traded in gems, did not have the gemological knowledge or instruments necessary to make the exacting identifications of today. Usually the location, color, and some simple physical characteristics like hardness, luster, crystal habit, and cleavage were the only basis for naming, and many incorrect identifications were made.

Examples can be seen in the misidentification of some of the famous gems of history, such as Cleopatra's emeralds (which were probably peridots). Or as in the case of the "Black Prince's Ruby" in the Crown Jewels of England, which turned out, upon testing, to be a spinel.

[Green rough stones, collected circa 1900 from the now exhausted St. Johns Island mine in Egypt, legendary home of Cleopatra's "emeralds": the gems are, in fact, peridot: Image courtesy of www.irocks.com]

Additionally, the folk name of a gem in one language may not have translated exactly, and may have innocently acquired new shades of meaning as the goods changed hands in international commerce.

Lists of such misnomers and folknames fill databases with thousands of items, many of which can still be found in use in various locations. Hopefully, as the level of gemological education and sophistication among both buyers and sellers grows, the majority of such terms will slowly drop out of circulation.

You can see from this short list that when a gem name that consists of a "modifier" in front of a recognized gem species or variety name, it is likely to be a misnomer. The material is most probably something else, not the gem (ruby, jade, lapis, etc.)-->usually something less valuable but with superficially similar characteristics. (Remember the distinction between a simulant and fake from Lesson 1: serpentine sold as faux jade or imitation jade is a simulant, serpentine sold as New Jade (which implies it is really a type of jade) is a fake, and the name is a misnomer.) 

In today's competitive world of marketing gems, misnomers are making something of a comeback. An example which can commonly be seen on TV shopping channels, in mail order catalogues, at flea markets, and even in retail stores is the term "white turquoise" for the mineral howlite, which is a creamy white with veins of darker color running through it. Gemologically, turquoise is defined by the presence of the copper in its chemical makeup. The copper content invariably gives it some shade of blue or green. So "white turquoise" is not only a misnomer, but an  oxymoron 矛盾修饰法as well.

Don't feel like a dummy 仿制品if you find that you've purchased something sold under a misnomer. It can happen to anyone--> here's a picture of a "smoky topaz" ring I bought from a well known retail jewelry chain, years before I became a gemologist. I still like it and wear it, even though I now know it's quartz and I paid way too much money for it. :-)