From your favorite gemstone to gemstones you've never heard of, we have fun facts and exclusive information in our new and improved gemstone encyclopedia.
Although this phosphate mineral has a hardness of 5.5, brazilianite is fragile due to its perfect cleavage and brittle nature. Most brazilianite is chartreuse to pale yellow and forms in granitic pegmatites associated with tourmaline and apatite.
Bronzite is an iron-bearing variety of enstatite distinguished by its green-brown color and bronze-like sub-metallic luster with fibrous inclusions. Enstatite is a silicate and a member of the pyroxene group. Appreciated for its sheen, bronzite is sometimes polished to make small ornamental objects.
Named in honor of its discoverer, Anastasio Bustamante, bustamite is a member of the wollastonite group. Similar to rhodonite in appearance, it is usually found as a massive transparent pink material that may be cut into cabochons or carved into figurines.
Bytownite is a rare variety of feldspar named for deposits found in Bytown, Canada (now Ottawa). Some forms of this gem distinctly resemble the gemstone andalusite, another member of the feldspar group.
Named for its calcium content, calcite is one of Earth's more abundant minerals-- you've probably seen it many times and not known exactly what it was. It is found in marble and limestone, as well as other rocks used in industrial settings. Gem-quality calcite, however, takes on a quite different look. You may have seen colorless calcite crystals used as examples for double refraction, but it also forms as white, gray, yellow, pink and green gems. Material is often faceted or polished en cabochon, or carved into ornamental objects.
Also called "rainbow calsilica," this is a man-made material that displays vibrant layers of bold color. It consists of a mixture of calcite, plastic and coloring pigments. This unique stone is often used in jewelry and carvings to show off its distinctive coloration.
Capiz Shells come from the province of Capiz and the island of Samal in the Philippines. The shells are often called windowpane oysters because they have been harvested for thousands of years for use as windowpanes. Capiz shells are also used today in chandeliers, lampshades, decorative objects, clothing decoration and jewelry. The shells are translucent in their natural state and turn opaque when heated. When shells are heated for longer periods of time, they turn a smoky brown color. Shells are also dyed fashionable colors.
Carnelian is a translucent orange to red variety of chalcedony. Uniformly colored cryptocrystalline quartz, its red tints are caused by traces of iron oxide. The name is derived from the Latin world for flesh, carnis, due to its orangey red color. Carnelian has been appreciated since antiquity, and is one of the first known materials ever to be used as a gemstone.
The name Cassiterite is derived from the Greek word kassiteros, meaning “tin.” Cassiterite is best known as a tin ore. Gemstones fashioned from cassiterite are quite striking. This is due in part to its high dispersion, which is nearly double that of diamond. It is especially prized by gemologists and mineralogists for its unusual, twinned crystal formations. Durable and dense, it has been used as the chief ore of tin throughout the ages. Cassiterite often exists in placer stream deposits where it collects as rounded, water-worn pebbles.
Very distinctive in appearance, cavansite is a rare, not to mention strikingly beautiful, blue mineral. Its name is derived from its composition: calcium, vanadium and silicon. Only discovered in the 1960's in Oregon, cavansite is highly sought after by mineral collectors across the globe. Found in a scant few locales, cavansite sources include Brazil, India, New Zealand and Oregon USA. It is renowned for its stunning deep blue hues that are sometimes vivid enough to be described as "electric blue."
Celestite, also called celestine, is named for the Latin coelestis, meaning "heavenly," in reference to its often sky-blue color. This unique gem often forms beautiful transparent to blue tabular crystals, but it can also be colorless, white, light red, green, blue or brown.
Named for the Latin word cerussa, meaning "white lead," cerussite is a lead carbonate mineral. It forms in several different crystal habits when carbonated water interacts with other lead minerals. Prized by mineral collectors for its twinned V-shape crystals that are transparent to translucent and are colorless to white, gray, brownish or greenish. Although too soft for jewelry, cerussite is occasionally faceted for collectors; however, it presents challenges to lapidaries due to its soft, brittle nature.
Chalcedony is a broad gemstone family of many varieties of cryptocrystalline quartz gemstones. Chalcedony usually has a waxy luster and appears in a great variety of colors including blue, white, buff, tan, green, red, gray, black, yellow or brown. Different colored varieties of chalcedony have individual names including agate (banded), bloodstone (green with red spots), chrysoprase (apple green), carnelian (orange to red), flint (dull gray to black), jasper (spotted red, yellow, brown or green) and sard (light to dark brown).
Named for the Greek khalkos meaning "copper," and "pyrite," chalcopyrite is a major ore of copper. It has a metallic luster, resembling gold. Specimens are often collected and are found in Colorado, Arizona in the USA, as well as England, Tasmania, Germany, Canada, Spain, Japan and China.
Charoite offers an intriguing, mystical array of patterns that are both eye-catching and mesmerizing. The patterns often exhibit a combination of swirls, veins and spots that give each piece a unique and magical appearance. The name Charoite is used to describe both a mineral and an attractive gem material primarily composed of charoite. The gem material comes from the remote, mountainous region of the Sakha Republic of Russia, which remains its only known source.
Chondrodite, named for the Greek word for grain, "chondros," is a member of the humite group of minerals. Its gemmy hues range from red to yellow to orange, with the latter resembling the color of spessartite garnet. It can be found in several places including New York, Burma, Tanzania, and Afghanistan.
Chrome diopside has several origins, but most of the finest material, and the only commercially viable deposit, is in the Republic of Sakha in Siberia, Russia. As you can imagine, production of this Siberian treasure is sporadic due to extreme winters that last more than eight months. The vivid greens of chrome diopside are a welcome alternative to rare and pricey emerald or tsavorite garnet, but it has yet to gain mainstream recognition due to its limited availability. Minor sources of chrome diopside include Australia, Austria, Canada, Finland, Italy, Madagascar, South Africa, and the United States.
First discovered in Tanzania in the 1960's, chrome tourmaline is a fairly new addition to the vast tourmaline family. A true collector's gem, chrome tourmaline exhibits bright green color that resembles, and even rivals, that of the finest emeralds. While it is a type of green tourmaline, not all green tourmalines contain chromium and can be called chrome tourmaline. True chrome tourmaline is more highly prized, as it is a more rare occurrence for chromium to be a coloring agent, which often results in a much brighter and richer green color.
Chrysoberyl is the name of a mineral as well as three different gem varieties two of which are widely accepted as some of the most rare and valuable of all phenomenal gems. The gem commonly known as chrysoberyl is a yellowish-green, brownish-yellow, or colorless transparent to translucent mineral that is usually faceted into gems and generally considered a collector's stone. While not often set in jewelry, its characteristics make it ideal for such use. When chrysoberyl displays color-change properties, it is known as alexandrite, and when it exhibits chatoyancy, it is known as cat's eye chrysoberyl.
Chrysocolla, derived from the Greek chrysos meaning "gold," is a copper mineral. Crystals are very rarely seen, but it is frequently intergrown with other minerals such as quartz or opal. This results in a harder, more resilient gemstone, as pure chrysocolla is soft and fragile. Its copper content is responsible for chrysocolla's range of bright green to blue hues.
One of the most coveted varieties of chalcedony quartz, chrysoprase is prized for its apple green color and rarity. Chrysoprase's name comes from the Greek words chrysos meaning “gold,” and prason meaning “leek,” due to its color similarities with the vegetable.
Named from Arabic and Persian words for "dragon's blood," cinnabar comes in a remarkable brick-red color and has been used as a pigment in China as far back as prehistoric times. Gem crystals are rare collector's pieces, but opaque material is often cut into cabochons. Natural cinnabar is a major mercury ore and is not used in jewelry making, but a resin product that closely resembles it, is used in jewelry. The red color is so fresh and vibrant that, in China, many people call it "China Red."
Citrine is one of the most popular gemstones in the quartz group. Prized for its excellent transparency, citrine is one of November's birthstones. Naturally, it occurs in close proximity to amethyst and is found in beautiful golden, mandarin orange and madeira red hues. It's possible that quartz crystals that grew naturally as amethyst or smoky quartz were turned into citrine by natural heat from nearby magma activity. Today, many of the citrines on the market are actually heated amethyst or smoky quartz.
A relatively new addition to the world of gems, clinohumite was first discovered in 1876 within stones erupted from Mount Vesuvius. Only recently have gem-quality pieces been found in locales including Tajikistan's Pamir Mountains. Clinohumite's coloring typically ranges from bright yellow to deep orange to red, but a few brown specimens have been found.