Gemology Introduction

Gemology Introduction

Gemology is the study of gemstones from a scientific perspective. While some investors and collectors are solely concerned with the monetary value of gems, they will require a scientific approach when it comes time to differentiate one gemstone from another. Whom are they going to seek out? Gemologists.

Reviewing the many sorts of gemologists and the work they do provides an excellent overview of gemology for collectors as well as those interested in careers in gemology.

Goldsmiths and Jewelers

Jewelers must have a working knowledge of gemology in order to answer their customers’ questions and correctly identify any gems brought to them.

Goldsmiths (and other metalworkers) must have a detailed understanding of the physical properties of gemstones in order to produce acceptable settings. For instance, a setting that is great for a diamond may cause damage to an opal, and the amount of pressure required to place the prongs on a garnet may fracture a tanzanite. Certain gemstones can resist the heat associated with high-temperature soldering repair procedures. Metalworkers can leave them in their settings if they take precautions. Other gemstones are so sensitive to heat that they would have to be removed.

Lapidaries

Additionally, lapidaries, or gem cutters, require specialized understanding. Cutting and polishing processes that are appropriate for each gem differ. What works well for one gemstone may be ineffective or even harmful for another. .The orientation of the rough by the cutters has a significant effect on the finished gem’s look. Cutting style is also considered to be a component of color control.

The cut of a gem has the ability to lighten or darken it, which has a significant effect on both the appearance and value of the stone. The shape, quantity, and placement of facets all have an effect on the gem’s brilliance. Lapidaries must take caution while selecting angles for facet cutting. They must take into account all of these elements in order to limit the quantity of gemstone rough sacrificed in order to make a stunning faceted gem.

The Experts

Although geologists, chemists, and even physicists make up a small percentage of gemologists, they are influential. The systematic recording and measurement of the physical and visual properties of gemstones is a well-established and continuous scientific procedure.

For centuries, the lapidary was best equipped to distinguish between diamonds with similar looks. Faceting provided a unique perspective on jewels that no other gemologist possessed. Numerous inclusions, elements trapped inside gemstones, and physical qualities, such as hardness, become obvious during the cutting and polishing of a gem.

Scientists continue to add to this body of knowledge by creating new testing techniques and conducting studies on newly discovered and manufactured gemstones.

 

Identification of Gemstones

The identification of gemstones lies at the heart of gemology. For instance, while some rubies and garnets appear identical, their actual qualities are somewhat different. The crystallography of ruby and garnet is highly variable. While the apparent shapes of each stone vary, their atomic crystal formations are distinctive. Garnets crystallize in an isometric or cubic system, whereas rubies crystallize in a hexagonal system.

Additionally, mineralogical techniques are employed to assist in the identification of gemstones.

Scratch tests, in which an unknown gem is scratched with various substances, are used to estimate its hardness. The way a gem reacts to acid and even heat can provide critical information about its identity. Naturally, these damaging tests are inapplicable to cut stones.

Additionally, scientists have developed non-destructive methods for identifying gemstones. They have developed tools that can be used to determine the physical and optical qualities of stones, such as their specific gravity and refractive index, without causing damage to them. Even anyone without substantial scientific expertise or access to pricey laboratory equipment can now use these methods to identify gems.

How to Begin in Gemology

If you’re interested in learning more about gems, you need to first understand how they’re classified and the terminology used to describe them. Following that, investigate their physical and optical qualities. With this background, you can begin studying gemstone identification.

Naturally, there are numerous side roads to explore while studying gemology. Perhaps you’ll develop an interest in with phenomenal gems or with inclusions found in natural gems. Individuals who collect gemstones may develop an interest in learning how to cut gems and create jewelry.

Whether you have a casual or professional interest in jewels, the world of gemstones will astonish you. Therefore, explore it from the comfort of your desk or get your hands dirty during a dig!

Throughout history, humans have used terminology such as “gem” and “gemstone” to refer to things such as rubies and emeralds. However, some individuals find defining a gem exceedingly difficult.

What Is a Working Definition of a Gemstone?

The following definition encompasses the vast majority of gemstones:

Minerals are selected for their beauty and durability before being cut and polished for use as human adornment.

Nonetheless, each defining characteristic of that definition has exceptions. This presents complications. 

Are All Minerals Gemstones?

While the majority of gems are minerals, some, most notably pearls and amber, are biological. These materials are produced by living creatures. A mineral, by definition, must be formed within the Earth. As a result, pearls are classified differently. (To add to the confusion, the coating of a pearl is a mineral, despite the fact that pearls from inside a mollusk.) Similarly, amber originated as tree sap. It evolved into a polymer, a type of natural plastic, over millions of years. For thousands of years, people have considered amber as a gem, despite the fact that it is not a mineral.

Is it necessary for a gem to be beautiful?

Some people find Pepto-Bismol pink and olive green colored gems unpleasant -such as unakite, a type of epidote. They are considered lovely by some. Brown gemstones are increasingly fashionable in “earth tone” jewelry. Naturally, some will have a different opinion. While beauty is subjective, does everyone who chooses gems to do so for beauty’s sake? Do all gem enthusiasts choose gemstones purely for their beauty?

How Long Must Gemstones Be Durable?

Durability is typically a top priority for gemstone purchasers. Nonetheless, two extremely popular diamonds are quite sensitive. Due to their softness, pearls normally survive for around a century as jewelry stones. The simple act of wiping away dust gradually erodes their protective coating. Perfumes and hairsprays, on the other hand, have the potential to ruin and damage pearls. Pearls require protective settings as ring stones, particularly for engagement rings.

Opals have been highly prized throughout history and are infamous for their fragility. They dry up and may crack as they lose their high water content. They are brittle and may break with the slightest provocation. They are also temperature sensitive.

Is it necessary to cut and polish all gemstones?

That concludes the discussion of beauty and durability. How about slicing and buffing? At the moment, many people enjoy wearing jewelry made entirely of whole crystals or “raw stones.” This was not the case decades ago. Mother Nature’s crystals can be quite lovely. Some believe they possess unique metaphysical properties that are amplified when they are left raw. As a result, we cannot require our gems to be cut and polished.

Is it possible to wear all gemstones as jewelry?

The final characteristic usually associated with a gemstone is its adornment value. Around 3,000 minerals have been cut, polished, and admired. Only about a hundred of these are used in jewelry. The rest are simply too delicate to wear well and belong solely in the domain of collectors.

Only in the 1930s was gemology recognized as a science. Until then, many people considered all transparent, red gems to be rubies, all blue gems to be sapphires, and all green gems to be emeralds. We can only refer to a crystallized beryllium-aluminum silicate containing trace amounts of chromium or vanadium as an emerald today. Tsavorites, tourmalines, diopsides, and even sapphires are additional stunning green gems.

Gemstones’ attraction is based on their fantasy of color and light. Since time immemorial, people have been fascinated by beautifully colored stones. The passion for gems has remained constant. However, we now encounter a highly scientific element. While we admire the science of gemology, it has the unintended consequence of removing much of the mystique and romance associated with our stones.

Ignore the definitions. If something makes your eyes sparkle, it’s a true gem!

Recognize Gemological Formula

A mineral’s chemical makeup is a critical part of its species definition. That composition can be described in a chemical formula that specifies the components and a proportionate number of atoms in a mineral molecule or chemical compound. Chemical formulas for minerals and other materials of interest in the worlds of jewelry and gem collecting are called gemological formulas. For instance, quartz has the chemical formula SiO2, which is composed of one silicon atom and two oxygen atoms.

Substitutions in Formulas for Gemstones

Numerous gemological formulas contain elements enclosed in parentheses separated by commas, such as (Fe, Mg). This implies that either iron (Fe) or magnesium (Mg), or both, may occupy a certain crystallographic position. Within a parenthesis, the element stated first is the one that is most abundant in the structural location. This is sometimes used to determine the species!

For instance, amblygonite is composed of (Li, Na) Al (PO4) (F, OH).

However, if the formula is (Li, Na) Al (PO4) (OH, F), a new species, montebrasite, is formed in which hydroxyl (OH) is more abundant than fluorine (F) (F).

Additionally, if the formula is (Na, Li) Al (PO4) (OH, F), sodium (Na) is greater than lithium (Li) (Li). As a result, we classify the mineral as a new species called natromontebrasite. * Clearly, the complexity associated with solid solutions might be rather high. Any element substitution at a crystallographic structural location may (or may not) alter the physical properties of the system.

Impurities

Additionally, impurities might have an effect on characteristics. Beryl, Be3Al2Si6O18, is an excellent example. Iron (Fe), manganese (Mn), chromium (Cr), vanadium (V), and cesium are frequently found in beryl (Cs). Due to the fact that these elements are typically present in trace amounts, they are not included in the gemological formula. There are, however, exceptions. For instance, when a beryl sample contains Cr (which imparts the rich green color known as emerald), gemologists know to substitute Cr for aluminum (Al) in the formula.

Detailed knowledge of chemical substitutions and color changes in crystals requires much greater sophistication in crystal-chemical principles

The International Mineralogical Association (IMA) discontinued the classification of natromontebrasite as a mineral species in 2006. It is now thought to be a blend of amblygonite, lapis lazuli, and wardite.