Learn About Gemstones

In this episode of the I Can't Sleep Podcast, fall asleep learning about gemstones. I've never been one for gemstones or jewelry, but now that I've learned more than I could hope to, I could see myself starting some side project where I buy lots of equipment to cut my gems. Yeah, I probably shouldn't do that. Happy sleeping!

Transcript

Welcome to the I Can't Sleep podcast, Where I read random articles from across the web to bore you to sleep with my soothing voice. I'm your host, Benjamin Boster. Today's episode is from a Wikipedia article titled Gemstone. A gemstone, Also called a fine gem, Jewel, Precious stone, Semi-precious stone, Or simply gem, Is a piece of mineral crystal which, When cut or polished, Is used to make jewelry or other adornments. Certain rocks, Such as lapis lazuli, Opal, And obsidian, And occasionally organic materials that are not minerals, Such as amber, Jet, And pearl, May also be used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, But some softer minerals, Such as brazilianite, May be used in jewelry because of their color or luster or other physical properties that have aesthetic value. However, Generally speaking, Soft minerals are not typically used as gemstones by virtue of their brittleness and lack of durability. Found all over the world, The industry of colored gemstones, I. E. Anything other than diamonds, Is currently estimated at around $1. 55 billion as of 2023 and is projected to steadily increase to a value of $4. 46 billion by 2033. A gem expert is a gemologist, A gem maker is called a lapidarist or gem cutter, A diamond cutter is called a diamanter. Traditional classification in the West, Which goes back to the ancient Greeks, Begins with a distinction between precious and semi-precious. Similar distinctions are made in other cultures. In modern use, The precious stones are emerald, Ruby, Sapphire, And diamond, With all other gemstones being semi-precious. This distinction reflects the rarity of the respective stones in ancient times, As well as their quality. All are translucent, With fine color in their purest forms, Except for the colorless diamond, And very hard, With a hardness score of 8 to 10 on the Mohs scale. Other stones are classified by their color, Translucency, And hardness. The traditional distinction does not necessarily reflect modern values. For example, While garnets are relatively inexpensive, A green garnet called savarite can be far more valuable than a mid-quality emerald. Another traditional term for semi-precious gemstones used in art history and archaeology is hardstone. Use of the terms precious and semi-precious in a commercial context is arguably misleading, In that it suggests certain stones are more valuable than others, When this is not reflected in the actual market value, Although it would generally be correct if referring to desirability. In modern times, Gemstones are identified by gemologists, Who describe gems and their characteristics using technical terminology specific to the field of gemology. The first characteristic a gemologist uses to identify a gemstone is its chemical composition. For example, Diamonds are made of carbon, C, And rubies of aluminum oxide, Al2O. Many gems are crystals, Which are classified by their crystal system, Such as cubic or trigonal or monoclinic. Another term used is habit, The form the gem is usually found in. For example, Diamonds which have a cubic crystal system are often found as octahedrons. Gemstones are classified into different groups, Species, And varieties. For example, Ruby is the red variety of the species corundum, While any other color of corundum is considered sapphire. Other examples are the emerald, Green, Aquamarine, Blue, Red beryl, Red, Cochenite, Colorless, Heliodor, Yellow, And morganite, Pink, Which are all varieties of the mineral species beryl. Gems are characterized in terms of their color, Hue, Tone, And saturation, Optical phenomena, Luster, Refractive index, Birefringence, Dispersion, Specific gravity, Hardness, Cleavage, And fracture. They may exhibit pleochroism or double refraction. They may have luminescence and a distinctive absorption spectrum. Gemstones may also be classified in terms of their water. This is a recognized gradient of the gem's luster, Transparency, Or brilliance. Very transparent gems are considered first-water, While second- or third-water gems are those of a lesser transparency. Additionally, Material or flaws within a stone may be present as inclusions. Gemstones have no universally accepted grading system. Diamonds are graded using a system developed by the Gemological Institute of America, GIA, In the early 1950s. Historically, All gemstones were graded using the naked eye. The GIA system included a major innovation. The introduction of 10x magnification as a standard for grading clarity. Other gemstones are still graded using the naked eye, Assuming 20-20 vision. A mnemonic device, The four Cs, Color, Cut, Clarity, And carats, Has been introduced to help describe the factors used to grade a diamond. With modification, These categories can be useful in understanding the grading of all gemstones. The four criteria carry different weights, Depending on whether they are applied to color gemstones or to colorless diamonds. In diamonds, The cut is the primary determinant of value, Followed by clarity and color. An ideally cut diamond will sparkle to break down light into its constituent rainbow colors, Dispersion, Chop it up into bright little pieces, Scintillation, And deliver it to the eye, Brilliance. In its rough crystalline form, A diamond will do none of these things. It requires proper fashioning, And this is called cut. In gemstones that have color, Including colored diamonds, The purity and beauty of that color is the primary determinant of quality. Physical characteristics that make a colored stone valuable are color, Clarity to a lesser extent, Emeralds will always have a number of inclusions, Cut, Unusual optical phenomena within the stone, Such as color zoning, The uneven distribution of coloring within a gem, And asteria, Star effects. Apart from the more generic and commonly used gemstones, Such as from diamonds, Rubies, Sapphires, And emeralds, Pearls and opal have also been defined as precious in the jewelry trade. Up to the discovery of bulk amethyst in Brazil in the 19th century, Amethyst was considered a precious stone as well, Going back to ancient Greece. Even in the last century, Certain stones such as aquamarine, Perido, And cadzai, Cymophane, Have been popular and hence been regarded as precious, Thus reinforcing the notion that a mineral's rarity may have been implicated in its classification as a precious stone and thus contribute to its value. Today the gemstone trade no longer makes such a distinction. Many gemstones are used in even the most expensive jewelry, Depending on the brand name of the designer, Fashion trends, Market supply, Treatment, Etc. Nevertheless, Diamonds, Rubies, Sapphires, And emeralds still have a reputation that exceeds those of other gemstones. Rare or unusual gemstones generally understood to include these gemstones, Which occur so infrequently in gem quality that they are scarcely known except to connoisseurs, Include andalusite, Axonite, Castorite, Klinehumite, Panite, And red beryl. Gemstone pricing and value are governed by factors and characteristics in the quality of a stone. These characteristics include clarity, Rarity, Freedom from defects, The beauty of the stone, As well as the demand for such stones. There are different pricing influencers for both colored gemstones and for diamonds. The pricing on colored stones is determined by market supply and demand, But diamonds are more intricate. Diamond value can change based on location, Time, And on evaluation of diamond vendors, Especially since most of the diamond supply in the world is strongly and exclusively controlled by a single authority, The beers. In addition to the aesthetic and adorning ornamental purpose of gemstones, There are many proponents of energy medicine who also value gemstones on the basis of their alleged healing powers. A gemstone that has been rising in popularity is Caprian Elbite Tourmaline, Which is also called Paraíba Tourmaline. It was first discovered in the late 1980s in Paraíba, Brazil, And later in Mozambique and Nigeria. It is famous for its glowing neon blue color. Paraíba Tourmaline has become one of the most popular gemstones in recent times thanks to its color, And is considered to be one of the important gemstones after rubies, Emeralds, And sapphires, According to Gubelin Gem Lab. Even though it is a tourmaline, Paraíba Tourmaline is one of the most expensive gemstones. There are a number of laboratories which grade and provide reports on gemstones. Gemological Institute of America, GIA, The main provider of education services and diamond grading reports. International Gemological Institute, IGI, Independent laboratory for grading and evaluation of diamonds, Jewelry, And colored stones. Ograd Voor Diamant, HRD, Antwerp, The Diamond High Council, Belgium is one of Europe's oldest laboratories. Its main stakeholder is the Antwerp World Diamond Center. American Gemological Society, AGS, Is not as widely recognized nor as old as the GIA. American Gem Trade Laboratory, Which is part of the American Gem Trade Association, AGTA, A trade organization of jewelers and dealers of colored stones. American Gemological Laboratories, AGL, Owned by Christopher P. Smith. European Gemological Laboratory, EGL, Founded in 1974 by Guy Marguel in Belgium. Gemological Association of All Japan, GAAJ-ZENHOKYO, Zenhokyo, Japan, Active in gemological research. The Gem and Jewelry Institute of Thailand, Public Organization, Or GIT, Thailand's national institute for gemological research and gem testing, Bangkok. Gemology Institute of Southern Africa, Africa's premium gem laboratory. Asian Institute of Gemological Sciences, AIGS, The oldest gemological institute in Southeast Asia, Involved in gemological education and gem testing. Swiss Gemological Institute, SSEF, Founded by Henry Hani, Focused on colored gemstones and the identification of natural pearls. Gubelin Gem Lab, The traditional Swiss lab founded by Eduard Gubelin. Institute for Gems and Gold Research of Vina Gems, Vietnam, Founded by Van Long Pham. Each laboratory has its own methodology to evaluate gemstones. A stone can be called pink by one lab while another lab calls it Padparascha. One lab can conclude a stone is untreated while another lab might conclude that it is heat-treated. To minimize such differences, Seven of the most respected labs, AGTA-GTL, New York, CISGEM, Milano, GAAJ-Zenokyo, Tokyo, GIA, Carlsbad, GIT, Bangkok, Gubelin, Lucerne, And SSEF, Basel, Have established the Laboratory Manual Harmonization Committee, LMHC, For the standardization of wording reports, Promotion of certain analytical methods, And interpretation of results. Country of origin has sometimes been difficult to determine due to the constant discovery of new source locations. Determining a country of origin is thus much more difficult than determining other aspects of a gem, Such as cut, Clarity, Etc. Gem dealers are aware of the differences between gem laboratories and will make use of the discrepancies to obtain the best possible certificate. A few gemstones are used as gems in the crystal or other forms in which they are found. Most, However, Are cut and polished for usage as jewelry. The two main classifications are as follows. Stones cut as smooth, Dome-shaped stones called cabochons or simply cab. These have been a popular shape since ancient time and is more durable than faceted gems. Stones which are cut with a faceting machine by polishing small flat windows called facets at regular intervals at exact angles. Stones which are opaque or semi-opaque such as opal, Turquoise, Verisite, Etc. Are commonly cut as cabochons. These gems are designed to show the stone's color, Luster, And other surface properties. Grinding wheels and polishing agents are used to grind, Shape, And polish the smooth dome shape of the stones. Gems that are transparent are normally faceted, A method that shows the optical properties of the stone's interior to its best advantage by maximizing reflected light and reducing the risk of distortion. Gems that are opaque or semi-opaque such as opal, Turquoise, Verisite, Etc. Are normally faceted, A method that shows the optical properties of the stone's interior to its best advantage by maximizing reflected light, Which is perceived by the viewer as sparkle. There are many commonly used shapes for faceted stones. The facets must be cut at the proper angles, Which varies depending on the optical properties of the gem. If the angles are too steep or too shallow, The faceting machine is used to hold the stone onto a flat lap for cutting and polishing the flat surfaces. Rarely, Some cutters use special curved laps to cut and polish curved facets. The color of any material is due to the nature of light itself. Daylight, Often called white light, Is all of the colors of the spectrum combined. When light strikes a material, Most of the light is absorbed while a smaller amount of a particular frequency or wavelength is reflected. The part that is reflected reaches the eye as the perceived color. A ruby appears red because it absorbs all other colors of white light while reflecting red. A material which is mostly the same can exhibit different colors. For example, Ruby and sapphire have the same primary chemical composition, Both are corundum, But exhibit different colors because of impurities which absorb and reflect different wavelengths of light depending on their individual compositions. Even the same-named gemstones can occur in many different colors. Sapphires show different shades of blue and pink, And fancy sapphires exhibit a whole range of other colors from yellow to orange-pink, The latter called padparadscha sapphire. A difference in color is based on the atomic structure of the stone. Although the different stones formally have the same chemical composition and structure, They are not exactly the same. Every now and then, An atom is replaced by a completely different atom, Sometimes as few as one in a million atoms. These so-called impurities are sufficient to absorb certain colors and leave the other colors unaffected. For example, Beryl, Which is colorless in its pure mineral form, Becomes emerald with chromium impurities. If manganese is added instead of chromium, Beryl becomes pink morganite. With iron, It becomes aquamarine. Some gemstone treatments make use of the fact that these impurities can be manipulated, Thus changing the color of the gem. Gemstones are often treated to enhance the color or clarity of a stone. In some cases, The treatment applied to the gemstone can also increase its durability. Even though natural gemstones can be transformed using the traditional method of cutting and polishing, Other treatment options allow the stone's appearance to be enhanced. Depending on the type and extent of treatment, It can affect the value of the stone. Some treatments are used widely because the resulting gem is stable, While others are not accepted, Most commonly because the gem color is unstable and may revert to the original tone. Before the innovation of modern-day tools thousands of years ago, People were recorded to use a variety of techniques to treat and enhance gemstones. Some of the earliest methods of gemstone treatment date back to the Minoan age, For example, Foiling, Which is where metal foil is used to enhance a gemstone's color. Other methods recorded 2, 000 years ago in the book Natural History by Pliny the Elder include oiling and dyeing or staining. Heat can either improve or spoil gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, And in many stone types, Heating is a common practice. Most citrine is made by heating amethyst, And partial heating with a strong gradient results in ametrine, A stone partly amethyst and partly citrine. Aquamarine is often heated to remove yellow tones, Or to change green colors into the more desirable blue, Or enhance its existing blue color to a deeper blue. Nearly all tanzanite is heated at low temperatures to remove brown undertones and give a more desirable blue-purple color. A considerable portion of all sapphire and ruby is treated with a strong gradient, A considerable portion of all sapphire and ruby is treated with a variety of heat treatments to improve both color and clarity. When jewelry containing diamonds is heated for repairs, The diamond should be protected with boric acid, Otherwise the diamond, Which is pure carbon, Could be burned on the surface or even burned completely up. When jewelry containing sapphires or rubies is heated, Those stones should not be coated with boric acid, Which can etch the surface, Or any other substance. They do not have to be protected from burning like a diamond, Although the stones do need to be protected from heat stress fracture by immersing the part of the jewelry with stones in the water when metal parts are heated. The irradiation process is widely practiced in the jewelry industry and enables the creation of gemstone colors that do not exist or are extremely rare in nature. However, Particularly when done in a nuclear reactor, The processes can make gemstones radioactive. Health risks related to the residual radioactivity of the treated gemstones have led to government regulations in many countries. Virtually all blue topaz, With the lighter and the darker blue shades such as London blue, Has been irradiated to change the color from white to blue. Most green cords, Or auvergne, Are also irradiated to achieve the yellow-green color. Diamonds are mainly irradiated to become blue-green or green, Although other colors are possible. When light to medium yellow diamonds are treated with gamma rays, They may become green, With a high-energy electron beam, Blue. Emeralds containing natural fissures are sometimes filled with wax or oil to disguise them. This wax or oil is also colored to make the emerald appear a better color as well as clarity. Turquoise is also commonly treated in a similar manner. Fracture filling has been in use with different gemstones such as diamonds, Emeralds, And sapphires. In 2006, Glass-filled rubies received publicity. Rubies over 10 carats with large fractures were filled with lead glass, Thus dramatically improving the appearance of larger rubies in particular. Such treatments are fairly easy to detect. Another treatment method that is commonly used to treat gemstones is bleaching. This method uses a chemical in order to reduce the color of the gem. After bleaching, A combination treatment can be done by dyeing the gemstone once the unwanted colors are removed. Hydrogen peroxide is the most commonly used product used to alter gemstones and have notably been used to treat jade and pearls. The treatment of bleaching can also be followed by impregnation, Which allows the gemstone's durability to be increased. Synthetic gemstones are distinct from imitation or simulated gems. Synthetic gems are physically, Optically, And chemically identical to the natural stone, But are created in a laboratory. Imitation or simulated stones are chemically different from the natural stone, But may appear quite similar to it. They can be more easily manufactured synthetic gemstones of a different mineral, Spinel, Glass, Plastic, Resin, Or other compounds. Examples of simulated or imitation stones include cubic zirconia, Composed of zirconium oxide, Synthetic moissanite, And uncolored synthetic corundum and spinels, All of which are diamond simulants. The simulants imitate the look and color of the real stone, But possess neither their chemical nor physical characteristics. In general, All are less hard than diamond. Moissanite actually has a higher refractive index than diamond, And when presented beside an equivalently sized and cut diamond, Will show more fire. Cultured, Synthetic, Or lab-created gemstones are not imitations. The bulk mineral and trace coloring elements are the same in both. For example, Diamonds, Rubies, Sapphires, And emeralds have been manufactured in labs that possess chemical and physical characteristics identical to the naturally occurring variety. Synthetic, Lab-created corundum, Including ruby and sapphire, Is very common, And costs much less than the natural stones. Small synthetic diamonds have been manufactured in large quantities as industrial abrasives, Although larger gem-quality synthetic diamonds are becoming available in multiple carats. Whether a gemstone is a natural stone or synthetic, The chemical, Physical, And optical characteristics are the same. They are composed of the same mineral, And are colored by the same trace materials, Have the same hardness and density and strength, And show the same color spectrum, Refractive index, And birefringence, If any. Lab-created stones tend to have a more vivid color, Since impurities common in natural stones are not present in the synthetic stone. Synthetics are made free of common naturally occurring impurities that reduce gem clarity or color, And less intentionally added in order to provide a more drab, Natural appearance, Or to deceive an assayer. On the other hand, Synthetics often show flaws not seen in natural stones, Such as minute particles of corroded metal from lab trays used during synthesis. Some gemstones are more difficult to synthesize than others, And not all stones are commercially viable to attempt to synthesize. These are the most common on the market currently. Synthetic corundum. Synthetic corundum includes ruby, Red variation, And sapphire, Other color variations, Both of which are considered highly desired and valued. Ruby was the first gemstone to be synthesized by Auguste Verneil, With his development in the flame fusion process in 1902. Synthetic corundum continues to be made typically by flame fusion, As it is most cost effective, But can also be produced through flux growth and hydrothermal growth. Synthetic barrels. The most common synthesized barrel is emerald, Green. Yellow, Red, And blue barrels are possible, But much more rare. Synthetic emerald became possible with the development of the flux growth process, And is produced in this way as well as hydrothermal growth. Synthetic quartz. Types of synthetic quartz include citrine, Rose quartz, And amethyst. Natural occurring quartz is not rare, Is synthetically produced, As it has practical application outside of aesthetic purposes. Quartz generates an electric current when under pressure, And is used in watches, Clocks, And oscillators. Synthetic spinel. Synthetic spinel was first produced by accident. It can be created in any color, Making it popular to simulate various natural gemstones. It is created through flux growth and hydrothermal growth. There are two main categories for creation of these minerals, Melt or solution processes. Vernal flame fusion process, Melt process. The flame fusion process was the first process used which successfully created large quantities of synthetic gemstones to be sold on the market. This remains the most cost-effective and common method of creating corundums today. The flame fusion process is completed in a vernal furnace. The furnace consists of an inverted blow pipe burner, Which produces an extremely hot oxyhydrogen flame, A power dispenser, And a ceramic pedestal. A chemical powder which corresponds to the desired gemstone is passed through these flames. This melts the ingredients which drop onto a plate and solidify into a crystal called a boule. For corundum, The flame must be 2000 degrees celsius. This process takes hours and yields a crystal with the same properties as its natural counterpart. To produce corundum, A pure aluminum powder is used with different additives to achieve different colors. Chromic oxide for ruby, Iron and titanium oxide for blue sapphire, Nickel oxide for yellow sapphire, Nickel chromium and iron for orange sapphire, Manganese for pink sapphire, Copper for blue green sapphire, Cobalt for dark blue sapphire. The Czochralski process, Melt process. In 1918, This process was developed by J. Czochralski and is also referred to as the crystal pulling method. In this process, The required gemstone materials are added to a crucible. A seed stone is placed into the melt in the crucible. As the gem begins to crystallize on the seed, The seed is pulled away and the gem continues to grow. This is used for corundum but is currently the least popular method. Flux growth, Solution process. The flux growth process was the first process able to synthesize emerald. Flux growth begins with a crucible which can withstand high heat, Either graphite or platinum, Which is filled with a molten liquid referred to as flux. The specific gem ingredients are added and dissolved in this fluid and recrystallized to form the desired gemstone. This is a longer process compared to the flame fusion process and can take two months up to a year depending on the desired final size. Hydrothermal growth, Solution process. A hydrothermal growth process attempts to imitate the natural growth process of minerals. The required gem materials are sealed in a container of water and placed under extreme pressure. The water is heated beyond its boiling point which allows normally insoluble materials to dissolve. As more material cannot be added once the container is sealed, In order to create a larger gem the process would begin with a seed stone from a previous batch which the new material will crystallize on. This process takes a few weeks to complete.