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Amethyst is the purple variety of the mineral quartz. Its color ranges from light lilac to deep royal purple, and it commonly shows color zoning. It is mined and can also be grown in a laboratory.

Ametrine is a transparent, bicolored variety of quartz (SiO₂) that shows the purple of amethyst and the yellow to orange of citrine in the same crystal; it is also called amethyst-citrine. Its name combines "amethyst" and "citrine". Mindat lists Bolivianite as a synonym (Spanish: Bolivianita). Natural ametrine comes commercially from a single source, the Anahí mine in Bolivia.

Angelite is a trade name for a translucent, light blue-gray, fine-grained anhydrite (natural calcium sulfate, CaSO4) from Peru. It is a natural mineral, not a separate species: mineralogically it is anhydrite. It is soft and is mainly cut into beads, spheres and carvings.

Apatite is the name of a group of natural calcium phosphate minerals, not a single species; most gems sold as apatite are fluorapatite. It is the reference mineral for hardness 5 on the Mohs scale. Transparent crystals in blue, blue-green, green, yellow and violet are faceted, while translucent material is cut as cabochons and beads.

Aquamarine is blue to greenish-blue beryl.

Aragonite is a natural calcium carbonate mineral (CaCO₃) with the same chemical formula as calcite but a different, orthorhombic crystal structure; the two are polymorphs. It is the second most common natural form of calcium carbonate, metastable relative to calcite, and often converts to calcite over time. It is also a main constituent of pearl and shell nacre and of ammolite.

Black star aquamarine is a trade name for natural beryl that looks dark brown to black because of dense, oriented inclusions, mainly of the iron-titanium oxide ilmenite, in an otherwise very light blue or pale green aquamarine host. The oriented inclusions give a sheen (schiller) and, in cabochons or beads, can show a six-rayed or even twelve-rayed star. Gemologists usually call it black beryl or star beryl; the dark appearance is linked to the inclusions and the brown colour zones around them, not to the pale aquamarine body colour.

Black tourmaline is a natural mineral, usually schorl, the iron-rich sodium tourmaline and the most common member of the tourmaline group. In the trade black tourmaline is sold as schorl, and the Japanese laboratory association AGL lists "schorl" as an alias of black tourmaline. It is common in granites, pegmatites and metamorphic rocks and is rarely used as a gem.

Blue calcite is a descriptive name for natural calcite (calcium carbonate, CaCO₃) with a blue colour; it is a colour variety, not a separate mineral species, and natural blue calcite is described as relatively rare. Its colour cause differs between deposits and remains debated: studies have linked it to defects from natural radiation, to transition metals such as iron, chromium, nickel and copper (Central Anatolia, Turkey), to copper in cave deposits and to trace elements in calcite from Madagascar.

"Blue moonstone" is a trade name for natural feldspar that shows a blue sheen; it is not a separate mineral species. GIA describes the most prized classic moonstone (orthoclase with albite layers) as colorless and nearly transparent with a vivid blue adularescence, known in the trade as "blue sheen". Material from Tanzania sold as blue moonstone in the mid-2000s was identified by the GAAJ laboratory as peristerite, a sodium-rich plagioclase feldspar, so the name alone does not tell which feldspar a stone is.

Blue topaz is the blue color variety of topaz, an aluminum fluorosilicate mineral. Natural strong blue topaz is extremely rare; almost all blue topaz on the market is natural colorless topaz whose color was produced by irradiation and heating, so it is a treated natural gem. The trade sorts it into color grades such as Swiss Blue (bright, lighter) and London Blue (dark).

Botswana agate is a natural variety of agate (banded chalcedony, SiO₂) from Botswana, banded with fine parallel lines and often coloured pink blending into white. It is mined mainly from the Bobonong area of the Central District, where the agates form in basalt of the Karoo volcanic rocks. It is a locality variety of agate, not a separate mineral.

Chrysocolla is a natural hydrated copper silicate mineral, (Cu,Al)2H2Si2O5(OH)4·nH2O, of secondary origin, coloured green, bluish green or blue by copper. Pure chrysocolla is very soft (Mohs 2.5 to 3.5) and crumbles too easily for cutting, while chrysocolla mixed with silica, such as quartz or chalcedony, is much harder and is a popular jewellery stone. It is often mixed with malachite, turquoise and other copper minerals.

Crackle quartz is treated natural quartz, not a separate mineral: the quartz is heated and then plunged into water, and the thermal shock fills it with a network of fine internal fractures ("quench crackling"). The fractures can show iridescent colors and also let dye enter, so crackled quartz is often dyed, sometimes to imitate more valuable gems.

Crazy lace agate is a natural variety of agate (banded chalcedony, SiO₂) whose bands twist and turn in many colours. The classic material comes from the Sierra Santa Lucia in Chihuahua, Mexico, where it occurs mainly as vein agate in limestone. It is a natural stone; like other agate, beads in unusually bright colours may be dyed.

Dragon agate (also sold as dragon vein agate) is a trade name for natural agate or chalcedony whose scale-like network of lines is man-made: the stone is heated and quenched to crack it, and dye is then drawn into the cracks. The base is a natural stone, but the pattern and most colours are treatments, so it should be described as treated (crackled and dyed) agate. GIA warns that such crackled chalcedony is sometimes misrepresented as fire agate.

Dumortierite is a natural aluminium borosilicate mineral that usually occurs as massive, fibrous or granular material in blue, violet-blue, pink or reddish brown. Massive blue and violet dumortierite is cut into cabochons and beads, while transparent faceted stones are very rare. It is a distinct mineral and should not be confused with dumortierite quartz, quartz rock coloured by dumortierite.

Emerald is the green to bluish green variety of beryl, a natural mineral species that also includes aquamarine and beryls of other colours. Its colour is caused by trace amounts of chromium or vanadium. Gemologists call paler stones green beryl rather than emerald, although opinions differ on where the boundary lies.

Eudialyte is a natural sodium-calcium zirconium silicate mineral of the trigonal eudialyte group, usually pink to deep red or brownish red. It forms in nepheline syenites and related pegmatites, and most gem material is massive rock from the Kola Peninsula, Russia, cut into cabochons, beads, spheres and carvings, often with black aegirine and white feldspar in the matrix. Transparent facetable crystals are rare and small.

Freshwater pearls on today's market are cultured pearls grown in freshwater mussels in lakes and ponds, mainly Hyriopsis cumingii (and hybrids) in China, the leading source. They are an organic gem made of nacre, not a mineral, and are the most commonly produced and most affordable pearl type, valued for their wide range of sizes, shapes and colours.

Garnet is not a single mineral but a group of closely related silicate minerals that share the same crystal structure and differ in chemical composition. Five species are commercially important as gems: pyrope, almandine, spessartine, grossular and andradite; a sixth, uvarovite, usually forms crystals too small to cut. Many garnets are chemical mixtures of two or more species. Garnets occur in almost every color, and red garnet is one of the most common and widespread gems.

Gray moonstone is a color name for natural moonstone feldspar with a gray body color, showing the soft moving sheen called adularescence. GIA notes that moonstone can be gray to nearly black and pictures a gray moonstone from India. It is a trade color name, not a separate mineral, and the sources read do not state which feldspar species such material is.

Green calcite is a descriptive name for natural calcite (calcium carbonate, CaCO₃) with a green colour; it is a colour variety, not a separate mineral species. A translucent green calcite from Pakistan examined by a gem laboratory contained trace copper and manganese, but the sources consulted do not establish the cause of the green colour. Some green calcite is artificially dyed: Mindat records "Mexican Jade" as dyed green calcite.

Green garnet is a color-based trade name for natural garnet, not a single mineral species. GIA names tsavorite and demantoid as green garnets: tsavorite is a green, chromium- and vanadium-bearing variety of grossular, and demantoid is the green to yellowish green variety of andradite. Other green grossulars, such as light "mint" garnet from Merelani, Tanzania, are also sold, while green uvarovite usually forms crystals too small to cut. A stone or bead sold as green garnet may therefore be any of these unless tested.

Iolite is the trade name for gem-quality, violet-blue cordierite, a natural magnesium-aluminium silicate mineral (Mg₂Al₄Si₅O₁₈) named after the French geologist Pierre Louis Antoine Cordier. It is known for strong pleochroism: turned in different directions, one stone can look violet-blue, pale blue-gray or almost colorless to yellow. Other recorded names include dichroite and the misleading "water sapphire"; iolite is not a sapphire.

Kunzite is the light pink to violetish purple variety of the natural mineral spodumene, a lithium aluminium silicate (LiAlSi2O6). Other spodumene varieties are green hiddenite and yellow triphane. It was named after the gemologist George Frederick Kunz and often occurs as large, relatively clean crystals.

Lapis lazuli is a blue rock containing several minerals.

Lava stone is a natural volcanic rock, not a single mineral. The porous rock known as "lava rock" corresponds to scoria or vesicular basalt: dark lava that solidified while full of gas bubbles, leaving many small cavities (vesicles). Its composition is usually similar to basalt, a rock made mainly of plagioclase and pyroxene.

Lavender amethyst is a trade name for amethyst, the purple variety of quartz (SiO₂), in a soft, pale lavender tone. The Japanese retailer Pascle uses the name for pale lilac to lavender amethyst (a trade claim). A 2024 study from the China University of Geosciences (Wuhan) describes a new type of amethyst sold as lavender amethyst whose main distinguishing feature is a milky texture, and found that the existing material had been heat-treated.

Lemon chrysoprase (also citron chrysoprase) is a misleading trade name: the material is not chrysoprase or any chalcedony but a natural, opaque, pale yellow to lime-green rock composed mainly of nickel-bearing magnesite (magnesium carbonate), often with quartz. Its green color is attributed to nickel, probably as gaspeite (nickel carbonate) in solid solution with the magnesite. Geologists suggest "lemon magnesite" or "citron magnesite" as more accurate names.

London Blue topaz is a trade name for the darker of the two dominant commercial color grades of treated blue topaz, a blue of moderate to dark tone and saturation. It is natural colorless topaz whose color was produced by irradiation; GIA's Gems & Gemology associates the London Blue color with neutron irradiation in a nuclear reactor. It is a treated natural gem, not a separate mineral or a locality.

Milky quartz is a natural variety of crystalline quartz (SiO₂) that is white and translucent to almost opaque. The white colour is not a pigment: it comes from countless evenly distributed tiny gas and/or fluid inclusions that scatter light. It is also called milk quartz or snow quartz, and the term is sometimes used for white, massive vein quartz.

Moonstone is a variety of the feldspar-group mineral orthoclase. As it forms, orthoclase and albite separate into thin alternating layers; light scattered between these layers produces adularescence, a soft glow that seems to billow across the stone. Hecatolite is a recorded synonym.

Morganite is the pink to orange-pink variety of beryl, the natural mineral species that also includes emerald and aquamarine. Its colour is caused by traces of manganese, and it is usually light in tone. Untreated morganite often has an orange component that gives a salmon or peach colour; much of it is heated to make it pinker.

Moss agate is a natural variety of chalcedony (microcrystalline quartz, SiO₂): a colorless to white, translucent stone containing green, moss-like inclusions of minerals such as chlorite or hornblende, sometimes with brown to black dendrites of iron or manganese oxides. Despite the name it is usually not banded like a true agate. Mindat lists tree agate and medfordite as synonyms; "mocha stone" is an older name used inconsistently by vendors.

Muscovite is a natural potassium-aluminium mica, KAl₂(AlSi₃O₁₀)(OH)₂, and the most common member of the mica group. Pure thin sheets are colorless to silvery white, but impurities tint it; Mindat notes that pink to red muscovite can owe its color to manganese (Mn³⁺) rather than lithium. The dark pink to red-brown beads sold as "muscovite" in the crystal trade are described by the Japanese retailer Pascle as manganese-colored muscovite, which is consistent with this, although no laboratory test of those beads was found.

Orange aventurine is an orange colour variety of aventurine, a natural quartzite or quartz rock whose small platy inclusions can make it glitter (aventurescence); the iron oxides hematite and goethite produce orange to red and brown tones. The Japanese retailer Pascle says its orange aventurine shows little aventurescence and is sometimes called orange quartzite. It is a natural rock, not goldstone glass and not sunstone feldspar.

Orange calcite is a descriptive name for natural calcite (calcium carbonate, CaCO₃) of orange to orangy-yellow colour; it is a colour variety, not a separate mineral species. Gem laboratories have documented orangy-yellow calcite from Pakistan and Mexico and yellowish-orange calcite from the Czech Republic. The sources consulted do not establish a cause for the orange colour, and the Japanese retailer Pascle notes that the boundary with yellow calcite is not defined, so names vary between sellers.

Orange garnet is a color-based trade name for natural garnet, not a single mineral species. GIA identifies spessartine (also called spessartite), a manganese aluminum garnet, as an orange garnet, and its purest, vivid orange form is sold as mandarin garnet; hessonite, the orange to brownish variety of grossular garnet, is also orange. Many garnets are mixtures of species, so a stone or bead sold as orange garnet may be either unless tested.

Orange moonstone is a color name for natural moonstone feldspar with a light orange to orange body color, showing the soft moving sheen called adularescence. GIA pictures light orange and orange moonstones from India among the many colors moonstone can have. It is a trade color name, not a separate mineral, and the sources read do not state which feldspar species such material is.

Peridot is gem-quality olivine, typically yellowish green.

Pink aventurine is a pink to reddish-brown colour variety of aventurine, a natural quartzite or quartz rock whose small platy inclusions can make it glitter (aventurescence). Its pink tones come from flakes of lepidolite mica or from the iron oxides hematite and goethite. The Japanese retailer Pascle describes the stone it sells under this name as pink to brownish red. It is a natural rock, not goldstone glass and not sunstone feldspar.

Pink calcite is a descriptive name for natural calcite (calcium carbonate, CaCO₃) with a pink colour; it is a colour variety, not a separate mineral species. In studied samples the pink colour is linked mainly to manganese replacing calcium (manganese-bearing, or manganoan, calcite). Cobalt-bearing calcite, which ranges from pink to purplish red, is another type.

Pink chalcedony is chalcedony, the microcrystalline form of quartz (SiO₂), in a pale pink color. Natural pink chalcedony exists, but because chalcedony is porous and easily dyed, pink chalcedony on the market may be natural or dyed. In the gem trade the plain name "chalcedony" is used for translucent stones of a single color, including pink.

Pink coral is an organic gem: the polished calcium carbonate skeleton of a colony of tiny marine animals (polyps), not a mineral. Untreated pink coral of jewellery quality is precious coral from the family Coralliidae, chiefly Pleurocorallium elatius (trade names momo, cerasuolo, satsuma; its light pink form is called angel's skin) and Pleurocorallium secundum (Midway, rosato). Much inexpensive pink coral in the bead trade is instead dyed: CIBJO notes that common bamboo coral is commonly bleached and dyed pink to imitate precious coral, so a dyed bead's species cannot be assumed.

Pink opal is a natural, opaque to translucent pink common opal: it shows no play-of-color. The best-known material comes from the Acari area of Arequipa, Peru, where studies found that most pink samples are opal-CT containing the fibrous clay mineral palygorskite, which is linked to the pink color. Similar palygorskite-bearing pink opal is also known from Mexico.

Pink tourmaline is the pink color variety of tourmaline, a group of boron silicate minerals; most gem tourmalines, including pink ones, are elbaite (liddicoatite also occurs). Its pink to red color is generally attributed to manganese, though some pink elbaites may owe their hue to color centers caused by natural or laboratory radiation. Deeper pink to red stones are sold as rubellite, although some in the trade argue that rubellite should not include pink tourmaline.

Prasiolite is a green, transparent variety of quartz (SiO₂). Most prasiolite on the market is produced artificially, by heating amethyst or by irradiating and heating quartz; natural occurrences are rare. It is often sold as "green amethyst", but Mindat calls that a highly confusing and officially discouraged trade name: the stone is green quartz, not amethyst.

Queen conch shell is an organic gem material, not a mineral: the shell of the queen conch (Aliger gigas, formerly Strombus gigas or Lobatus gigas), a large Caribbean sea snail. Its pink, cream and white shell is made of aragonite with a porcelain-like, non-nacreous luster and a silky "flame" structure; it is not mother-of-pearl. The species is listed in CITES Appendix II, so international trade in it, including its shell, is regulated under CITES.

Rhodochrosite is a natural manganese carbonate mineral (MnCO3) of the calcite group, pink to rose-red in color. "Inca Rose" is a trade name for the same mineral. Banded massive material is cut into beads, cabochons and carvings; rare transparent crystals are faceted for collectors.

Rhodolite is a natural purplish red garnet whose composition lies in the pyrope–almandine series. Mindat notes that the name originally meant a rose-red gem variety of pyrope but now covers pink to purplish garnets in that series, many of them closer to almandine. IGS stresses that the purplish red hue, not an exact recipe, defines rhodolite, and that small amounts of other garnet species are always present.

Rhodonite is a natural manganese silicate mineral (rhodonite group, triclinic) with a pink to rose-red color, often veined with black manganese oxides. Massive, opaque material is widely carved into beads, cabochons and objects, while transparent faceted stones are rare because of the mineral's perfect cleavage.

Rock crystal is the traditional name for clear, colourless quartz (silicon dioxide, SiO₂), a natural mineral. It is one variety of quartz, not a name for the whole quartz family: coloured varieties such as amethyst, citrine and rose quartz have their own names. Except for being colourless and clear, it has no property that other crystalline quartz lacks.

Rose quartz is pink quartz, commonly translucent.

Ruby is the red variety of corundum (aluminium oxide), a natural mineral species that also includes sapphire. Pure corundum is colourless; ruby's red, ranging from orangy red to purplish red, is caused by traces of chromium, which can also cause red fluorescence. Corundum of any other colour is called sapphire.

Ruby in zoisite, also called anyolite, is a natural metamorphic rock rather than a single mineral: bright green chromium-bearing zoisite containing opaque purplish-red to pink ruby (corundum) crystals, often with black to very dark green amphibole (pargasite, also described as hornblende or tschermakite). It was first reported in 1954 near Longido, Tanzania, and is cut into cabochons, beads, carvings and small sculptures.

Santa Maria aquamarine is a trade name for aquamarine (blue beryl, a natural mineral) of a rare, medium-dark, highly saturated blue. The name comes from the Santa Maria de Itabira mine in Minas Gerais, Brazil, which is now nearly exhausted; today the trade uses it mainly for a colour rather than a locality, including stones from African deposits. It is not a separate mineral species.

Sardonyx is a natural banded chalcedony (cryptocrystalline quartz, SiO₂), classed by Mindat as a variety of agate, in which brownish red to orange layers of sard alternate with white or black layers of onyx. It is one of the three August birthstones and, according to GIA, the original one. Mindat lists "carnelian onyx" as a synonym.

Sea Blue Chalcedony is a trade name for natural chalcedony (microcrystalline quartz, SiO₂) that has been dyed a vivid light blue; the color is not natural. It was introduced at the Tucson gem shows in February 2002 by the supplier Maxam Magnata of Tucson, Arizona, as color-enhanced chalcedony, later described by the company as a dyed translucent material sold as Sea Blue Chalcedony™.

Seraphinite is a trade name for a natural, dense, fine-grained variety of clinochlore, a soft magnesium-aluminium silicate of the chlorite group, whose radiating, feather-like (plumose) structure gives a silvery shimmer on a dark green to grey ground. It is used for carving and as a decorative stone. Mindat records it from the Korshunovskoye iron deposit in Irkutsk Oblast, Siberia, Russia.

"Shell pearl" is a man-made imitation pearl, not a natural or cultured pearl: a bead cut from mollusk shell is coated with an artificial pearly layer to look like a pearl. GIA considers the name misleading; under CIBJO rules such products must be called "imitation" or "simulated" pearls.

Soapstone, also called steatite, is a natural metamorphic rock made mostly of the soft mineral talc, with varying amounts of chlorite, micas, amphiboles, pyroxenes and carbonates. It is named for its soapy feel and softness, and is usually gray, bluish, green or brown. The pink beads sold in Japan as "soapstone" or "pink talc" were reported by the retailer Pascle, citing a Japanese gem laboratory, to be natural talc with a wax-coated surface; the sources read here do not explain their pink color. The word "soapstone" is also used loosely in the craft trade for other soft rocks such as alabaster or serpentine.

Stichtite is a natural, very soft, rose-pink to purple mineral, a hydrated magnesium-chromium carbonate-hydroxide of the hydrotalcite group, named after Robert Carl Sticht of the Mount Lyell Mining and Railway Company in Tasmania. It forms in altered serpentinites with chromite, and is often found mixed with green serpentine.

Sunstone is a feldspar gem material; its sparkling varieties contain reflective inclusions. Both orthoclase and plagioclase feldspars have sunstone varieties, so the name describes appearance rather than chemistry. Heliolite, sun stone and aventurine feldspar are alternate names.

Super Seven (also sold as Sacred Seven or Melody Stone) is a trade name, not a mineral name, for natural quartz, mostly amethyst and smoky quartz, that contains inclusions of other minerals. Sellers claim it holds seven minerals: amethyst, clear quartz, smoky quartz, rutile, goethite, lepidocrocite and cacoxenite. Three of these are colour varieties of quartz itself, and Mindat managers report that pieces on sale never showed all seven and that the "cacoxenite" and "lepidocrocite" were often really goethite and hematite.

Unakite is a natural rock, not a single mineral: an altered granite made chiefly of pink orthoclase feldspar, green epidote and white to smoky quartz. The epidote formed secondarily, replacing the mica or hornblende of the original granitic rock. It takes a high polish and is used as an ornamental stone.

Vesuvianite is a natural silicate mineral, a calcium-aluminium sorosilicate with variable magnesium and iron, recognised by the IMA as a valid species. It is also widely known as idocrase, an older name that is still common in the gem trade. Transparent crystals are faceted as collector gems, while compact green material is cut into beads and cabochons or used as a jade substitute.

White chalcedony is natural chalcedony, the microcrystalline form of quartz (SiO₂), in a white to off-white color. Pure chalcedony is white, gray or bluish; other colors come from included minerals. In the gem trade the plain name "chalcedony" is used for translucent stones of a single color, and white is one of the colors sold this way.

Yamanashi crystal is natural quartz (SiO₂) mined in Yamanashi Prefecture, Japan, mainly in the granite mountains around Mount Kinpu (Kinpusan). It is a locality name, not a separate mineral: the deposits yielded colourless rock crystal as well as white, smoky, chlorite-included and, rarely, amethyst quartz. Mining flourished in the Meiji era and has since ended; the largest mine, Otome, closed in 1981.

Yellow opal is natural common opal with a yellow body color and no play-of-color. Common opal is usually white, gray or brown, but traces of other substances can color it yellow, orange, green, blue or pink. Transparent to translucent yellow to red opal is also classed as fire opal, so the boundary between yellow common opal and yellow fire opal is not sharp. The Japanese retailer Pascle also calls it "banana opal".