Technical Information on Gemstones

Advanced Gem Analysis

Gemstone identification increasingly depends on high tech instruments such as FTIR, EDXRF and LIBS

African Tsavorite Gemstones - 100 per cent naturally green

Tsavorite is a rare vivid green grossularite garnet, colored by chromium or vanadium, with deposits mainly in East Africa.

All About Gemstone Treatments - Information

Many gemstones today are treated with various methods to improve color and quality. Learn about the latest treatments and how they are detected.

Alternative Metals for Jewelry-Making

Alternative metals such as stainless steel, tungsten carbide and titanium can be used to make modern jewelry. Read more about other metals for jewelry-making

Ancient Turquoise Gemstones - Desired from east to west

Blue-green turquoise has long been admired and used by Native Americans in the Rocky Mountains of the west and by Persians in the bustling bazaars of the east.

Asscher Cut Gemstones

The Asscher cut is a modified emerald cut with a square shape, cut corners and a deep pavilion. The result is greater brilliance and fire

Beryllium Treatment for Gemstones 'Be Heated' - Gemstone Informa...

Gemstone Treatments are nothing new, but beryllium gemstone enhancements (Be heated) to improve color is a recent innovation that has made gems more afford...

Brilliance, Luster and Fire

These are important technical terms in gemology, but they are often misused. Learn how to use these terms correctly to describe gemstones.

Buying Aquamarine - What you should know before you buy

Read about this beautiful gemstone, what to look for when you are buying and what to avoid. What is most important when buying aquamarine - the cut

Carats and Karats

Gemstones are weighed in carats, while the purity of gold is measured in karats.

Certified Gemstones

Many gemstone are certified to guarantee their authenticity. But not all gem certificates are created equal

Clarity and Cut - Gemstone Information

All about gemstone clarity and cut in precious and semi-precious gemstones. Learn how colored gems are graded for clarity - and about the many gemstone cut...

Classifying Gemstones: How Gemstones Types Are Classified

Gemstones are classified by species, groups, types and varieties; and are assigned to the 10 mineral classes. Learn more about how precious and semi-precio...

Color Change Fluorite Gems

Color change fluorite is a rare gem that displays a color change under different lighting conditions, often from blue in daylight to purple under incandesc...

Colored Gemstone Clarity Grade Table

Clarity grading for colored gemstones is not as simple as for white diamonds, colored gemstones are categorized into 3 types, and are then graded for clarity

Concave Cut Gemstones

Concave cutting is a recent innovation that uses curved rather than flat facets, resulting in a more brilliant gem. But not everyone is impressed

Copper-Bearing Gemstones

Ever since the discovery of paraiba tourmaline, the market is excited about copper-bearing gems. What's so special about copper?

Cubic Zirconia Info

Cubic zirconia, a synthetic gemstone, became the most successful diamond simulant on the market

Culet in Cut Gems

The culet is the tiny facet at the very bottom of many faceted gemstones. Some gems are cut with a closed culet.

Cutting Gemstones - Gemstone Information

Cutting gemstones is known as lapidary work, and the shaping, engraving, faceting and polishing of stones is performed by a person known as a lapidary

Detecting Gem Treatments

Gem treatments should always be disclosed, but not all enhancements can be detected, even by the best gem labs

Detecting Synthetic Quartz

Synthetic quartz has become very common in the gem market. Distinguishing synthetic from natural quartz takes considerable expertise.

Diamond and Graphite

Diamond and graphite have the same chemical composition, but they are as different as could be.

Diffusion Treatment for Gemstones

Diffusion treatment of gemstones is controversial, and may affect the ability to recut the stone in the future.

Discover Rare Clinohumite Gems - Unique & Valuable

Clinohumite is a rare mineral and an especially rare gemstone. It is a member of the humite group of minerals, which includes humite, clinohumite, chondrod...

Druzy Gemstone Info

Druzy (druse or druzy) refers to encrustations or clusters of minute crystals in a matrix

Emerald Treatments

Natural emeralds tend to have surface-reaching fissures and are treated with oils, resins or polymers

Exploring Epidote and Unakite: Unique Gems with Distinctive Appeal

Explore the world of Epidote and Unakite, two intriguing minerals known for their unique characteristics and diverse applications in gemology.

Faceted Gemstones

The art of faceting enhances the brilliance and luster of gemstones. Buy faceted gemstones online at GemSelect.

Finest Red Rhodolite Garnet

Rhodolite, the rose-red to violet-red garnet, is a mixture of almandite and pyrope. It has the best red of any garnet.

Fracture Filled Treatment - Gemstone Information

Fracture filling is a common enhancement for emeralds, turquoise and a number of other gemstones. Learn about fracture filling and other gem enhancements a...

Fracture-filled Ruby

Why are so many fracture-filled rubies being offered in the market? Should you buy one?

Gem Pavilion, Girdle and Crown Guide

A GemSelect guide to colored gemstone anatomy, learn how to identify a gem's pavilion, girdle and crown, and about different cutting styles and why they a...

Precious and Semi-Precious Gemstone Glossary

Gemstone & Mineral Glossary - Gemstone Information

A comprehensive glossary of terms used to describe colored stones, precious and semi-precious gems, minerals and gemstone jewelry. Gemstone and Jewelry Inf...

Gemstone Carat Weight - Gemstone Information

Like diamond, colored stones are graded by the 4 c's. Carat weight is very important when it comes to gemstone value, along with color, clarity and cut - ...

Gemstone Clarity Scale - Gemstone Information

GemSelect grades colored gemstones according to the following clarity scale: IF, VVS, VS, SI and I1, type 1, type 2 and type 3 should also be taken into account

Gemstone Cleavage Chart - Gemstone Information

Chart with cleavage ratings for more than 110 varieties of gemstones. Learn which gemstones have perfect cleavage and which have none at all.

Gemstone Color - A Quick Guide to Colors

A gemstone's color is its most defining characteristic. When deciding upon gemstone color you want to consider hue, tone, and saturation

Gemstone Color Saturation - Find all Details here

Color saturation, sometimes known as chroma, is a measure of the purity or intensity of color hue. Highly saturated colors are highly valued in gemstones.

Gemstone Dispersion Chart Information

Looking for gemstones with significant fire? Here is a chart that ranks many gem varieties by their dispersion or fire.

Gemstone Doublets: Elegance & Durability Combined

A gemstone doublet is a composite stone made up of a natural gemstone and a less expensive material. Opal doublets are commonly found in the market.

Gemstone Hardness | Mohs Scale with Images and Charts

What is the toughest gemstone? Which ones are easily scratched? These questions are many more answered in our informative article on gemstone hardness. Moh...

Gemstone Hardness and Durability

Hardness is only one measure of a gem stone's durability. Learn what other properties are important.

Gemstone Identification

Trying to identify gemstones has become more challenging with the advent of new treatments and synthetics. What once was an art has become a science.

Gemstone Information

The most comprehensive library of gemstone information on the internet. Info on more than 80 varieties of gemstones.

Gemstone Laboratories

In the gem trade, gemological labs have the last word in gemstone identification. A recent lawsuit shows that might not always be true.

Gemstone Names | Gem Name Origins, History, Lists and More

Discover all Gemstones Names and Investigate the origins and meanings behind the fascinating and often bizarre names of gemstones we love and desire.

Gemstone Scintillation

Well-cut faceted gemstones display 3 different illumination effects: brilliance, scintillation and fire

Gemstone Shape and Cut - What is the difference?

You may think shape, cut and facet all mean the same thing but read this article to discover the differences between pear shape, rose-cut and a faceted pavilion

Gemstone Testers

Gemstone testers are becoming useful. But they are still no substitute for a trained gemologist.

Gemstone Trade Names

Some marketing names for gemstones have succeeded; others, thankfully, have failed.

Gemstone Treatment Disclosure

The Federal Trade Commission defines the rules for disclosing gemstone treatments. These rules may not go far enough

Gemstone Treatments: Stabilization and Impregnation

Stabilization and impregnation are gemstone enhancements that improve the hardness, density, color and durability of naturally fragile gemstones, especiall...

Gemstones that Sparkle - Which ones have the most dazzle?

Diamonds are the most famous sparklers but there are a few gemstones such as zircon and sphene that could be even more brilliant. See our top ranked stones...

Gentle Heat Treatment

The term -gentle heat- for the heat treatment of sapphire and ruby is seriously misleading, and should be avoided

Green Zircon Facts and Buying Guide | Gem Insights

Discover the appeal of Green Zircon with our essential guide. Uncover the gemstone's benefits, properties, and tips.

Heat Treatment - Gemstone Information

Some gemstones are routinely heated to improve their color and clarity. Learn how heat treatment works and how it can be detected.

Hemimorphite Gems

Gem-quality hemimorphite is usually blue or green, and bears some similarities to chrysocolla, smithsonite and turquoise.

History of Briolettes

The briolette, a pear-shaped gemstone with geometric facets, is one of the oldest styles of cut gems.

How Gemstones are Formed: Learn about the processing of Gems - Gem...

Most gemstones form in the Earth's crust. Only two gemstones, diamond and peridot, form in the mantle. Learn about how gemstones form.

How Gemstones Get Their Colors

Some gemstones get their color from their essential chemistry; others from trace elements or impurities. Learn how the different gem varieties get their color.

Hydrothermal Quartz - Gemstones created in the laboratory

Scientists can now recreate the work of mother-nature by creating colorful quartz crystals on demand. Are they real quartz crystals? Can you tell them from...

Iolite Rarity Explored: Learn about Iolite Facts and Secrets

Iolite gemstones with good color saturation and clarity are rare in sizes over 1 carat.

Irradiation Treatment - Gemstone Information

All about the irradiation of gemstones to improve their color.

Kyanite Hardness

Kyanite is an unusual gemstone because it has a highly variable hardness, depending on the direction of the crystal.

Labradorite Iridescence: Discover the Mystic Glow

Labradorite is an iridescent gemstone with a fascinating metallic luster when viewed from certain angles. Iridescence is also found in a variety of other g...

Lighting and Gem Color

Gemstone color appears differently under different kinds of light. But how many kinds of light are there?

Making Mystic Topaz and Mystic Quartz: Enhancement Techniques Explained

Discover how colorless topaz and quartz are transformed into vibrant mystic gems using advanced thin-film coating technology. Learn about the process, characteristics, care, and more in this comprehensive guide.

Minerals, Rocks and Gems

What is the difference between a mineral, a rock and a gemstone? You'll find some answers here.

Natural Gemstones, Unnatural Names

Buy loose gemstones even if you can't spell padparasha, pariba, saphire, alexanderite, dimond, tanzinite or andasine.

Organic Gemstones - Certain gemstones are not stones at all

Most gemstones are crystals but some of our most famous precious gems are organic in origin, forming from animal or vegetable - pearls, amber, coral and am...

Paraiba Tourmaline Gemstones - Brazil's dazzling discovery

It is not often that a new gemstone appears and the arrival of the vivid neon blue of the Paraiba Tourmaline took the world by storm shortly after it was d...

Peridot Gemstones

Peridot, the birthstone for August, has many unusual qualities. Unlike most gemstones, peridot is formed deep within the earth.

Pezzottaite Gemstones

Pezzotottaite, a rare gem first discovered in Madagascar, is often confused with red beryl.

Planetary Gemology

Planetary gemologists prescribe gems based on astrological principles. Using the right gems is said to enhance health, wealth, power and popularity.

Pleochroic Gemstones

Some gemstones display different colors when viewed from different angles. Andalusite, iolite, kyanite, kunzite, sphene and tanzanite exhibit pleochroism t...

Prong Vs. Bezel Settings

Prongs and bezel settings have advantages and disadvantages. Learn about prong (or claw) settings and bezel settings for gemstone jewelry.

Raman Spectroscopy

Scientists are using Raman spectroscopy to identify gemstones and minerals with a Star Trek-style tricorder device.

Rare Sillimanite Gems

Sillimanite is a rare collector's gemstone that is colorless, grayish-white, green, bluish or brownish hues. Transparent, faceted sillimanite gems are ext...

$Refractive Index Chart$

Refractive Index Chart of Gemstones - What does it mean and how do...

A chart of the refractive indices for more than 200 varieties of gemstones. Find quickly all the data you need.

Seeing Gemstone Stars - Asterism Effect Information

Learn how to evaluate star gemstones, and why the star may not be easy to see under diffused light. Gemstones that display the star effect, known as asteri...

Semi-Precious Gemstones - The Diverse World of Semi-precious Gems

The world of semiprecious stones is incredibly diverse. Some are as rare and valuable as any precious stone. Others are very affordable. In between is a re...

Simulants Vs. Synthetics - Gemstones

Fake gemstones may be synthetics or simulants. Learn how to identify the difference between these.

$Singly Refractive Gems$

Singly Refractive Gems

Diamond, garnet and spinel are well known as belonging to the small group of singly refractive gemstones. But there also are some lesser known members of t...

Specific Gravity Chart - Gemstone Information

Specific gravity is the term for the relative density of a gemstone. This chart shows the specific gravity for more than 60 varieties of gemstones.

Spessartite Garnet: Discover Its Unique Appeal

Uncover what is special about Spessartite Garnet. Explore its vibrant colors, origins, and unique properties that make it a gemstone connoisseur's treasure.

Sphene Brilliance

Sphene is one of very few gemstones with an adamantine or diamond-like luster. Sphene's dispersion or fire even exceeds diamond.

Spudomene Species - From industrial use to the jewelry store

Spudomene is a major source of the lithium found in batteries around the world but the pink gemstone Kunzite is a spudomene and so is the green Hiddenite

Star Diopside the Phenomenal Black Star of India

Star diopside is known in the gem trade as the Black Star of India. Not as well known as chrome diopside, but special and unique with asterism chatoyancy -...

Star Gemstones

Star sapphire and star ruby are examples of gems that exhibit asterism or the star effect. Learn why some gemstones exhbit this rare phenomenon.

Synthetic Emerald - Gemstones grown in the laboratory

Scientist, Carroll Chatham, experimented in his laboratory for many years before finally succeeding in creating an synthetic emerald, a one carat crystal n...

Synthetic Moissanite - Diamond Substitute or Gem on its Own?

Moissanite is the latest diamond simulant to hit the market, with a hardness and density more diamond-like than cubic zirconia

Synthetic Ruby and Sapphire - Flame Fusion Method

In 1902 the French chemist Verneuil invented the flame fusion method for creating synthetic corundum. It is still being used today.

Taaffeite Gemstones - Rare Gemstone Varieties

Taaffeite is one of the rarest gem varieties in the world. It has many similarities to spinel, but is doubly refractive

Tension Settings

Tension settings use compression to hold a gemstone in place. The designs are stunning, but are these setting secure?

The Mystery of Andesine-Labradorite

An attractive red feldspar called andesine has attracted a lot of attention in the gems world. What is really known about andesine?

Understanding Color Zoning in Gemstones: A Comprehensive Guide

Discover Color Zoning in Gemstones with our in-depth guide. We explain how this fascinating phenomenon affects the beauty and value of precious stones.

Understanding Gemstone Cleavage

Some gemstones, including diamond, topaz, tanzanite and fluorite, have perfect cleavage. Learn about why this is important.

Untreated Gems for Jewelry - Part II

There are many untreated colored gemstones that come from the mines to the market completely natural and unenhanced, such as opal, tourmaline, quartz, spin...

Untreated Gemstones

Some varieties of gemstones are never treated, and they represent exceptional value in today's gem market.

Uvarovite Garnet: Rare Green Gem Properties & Origins | GemSelect

Explore uvarovite garnet, the rarest garnet with a vivid emerald-green hue. Learn about its unique properties, Russian origins, jewelry uses, and care tips.

Valuable Gemstone Inclusions

Conventional wisdom about colored gemstone inclusions is that less is more. But some inclusions are valuable.

What is a Natural Sapphire? | Treatments, Synthetics, and Gemstone Insights

Explore the definition of natural sapphires, differences from synthetics, common treatments like heating and lattice diffusion, and their impact on value. Dive into sapphire information, meanings, valuable examples, and market cautions.

Why are Some Gems Cut as Cabochons?

What are gemstone cabochons, and why are some gemstones cut as cabochons and others as faceted gems?

World of Quartz – Much more than Amethyst and Citrine

Tiger's Eye, Onyx, Jasper, names to fire your imagination. Discover the wide world of quartz in this article which reveals the colorful characters that l...

Zircon and Zirconology - The Study of Zircon

Zircon is the oldest mineral on Earth, over 4.4 billion years old. It is also a fine gemstone with great brilliance and fire.

Zultanite, Csarite and Diaspore: Color Change Diaspore Gemstones -...

Zultanite, Csarite and Diaspore are all names for a color change gemstone from Turkey. What is color change diaspore and why does it have many names?