Key properties
| Chemical formula | Amorphous organic polymers (varies: acrylic, polystyrene, celluloid, phenolic/Bakelite, epoxy, polyester) |
| Crystal system | Amorphous |
| Mohs hardness | 1.5-3 |
| Toughness | Fair |
| Refractive index | 1.460-1.700 |
| Optic character | Single refractive; strong anomalous double refraction and strain colours common |
| Specific gravity | 1.05-1.55 |
| Cleavage | None |
| Fracture | Conchoidal to uneven |
| Habit | Injection-moulded or cast beads, cabochons and 'faceted' stones; hand-carved vintage Bakelite |
| Lustre | Dull to vitreous; waxy to greasy on moulded surfaces; polish: Waxy to vitreous |
| UV fluorescence | Variable - acrylic often bluish or orange; dyed types may glow; many inert. |
| Pleochroism | None. |
| Cause of colour | Organic dyes and inorganic pigments dispersed in the polymer; any colour can be produced. |
| Typical inclusions | Round gas bubbles, flow lines, mold seams, orange-peel surfaces, concave 'facets' with rounded junctions; embedded glitter or foils in novelty products |
| Stability | Attacked by many solvents, acids and alcohol; surfaces dull and scratch with wear; heat melts or burns it. |
| Heat sensitivity | Extreme - melts or scorches at low temperatures with an acrid (or carbolic, for Bakelite) smell. |
| Care and cleaning | Warm soapy water, soft cloth; never ultrasonic or steam; keep away from perfume, solvents and heat. |
| Availability | Plentiful in every colour at negligible cost. |
| Recognition | Universal as a material; the gemmological skill is separating it quickly from the organics it imitates. |
Varieties (11)
Plastic — Red-Pink
| Colour | transparent reds and pinks, candy-bright |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Lolly-like red with a waxy-vitreous skin; moulded surfaces show orange-peel texture. |
| Trade names | acrylic • epoxy resin • polyester resin |
| Misnomers | 'Crystal' and 'ruby' claims on novelty goods |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded brilliants and beads; sometimes hand-carved |
| Key separations | vs ruby/garnet/spinel: all are much heavier (SG 3.5-4.2 vs plastic 1.05-1.55), much harder (7+ vs 1.5-3), cool to the touch, and show no mold seams. A needle pressed in dents plastic. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (ruby, garnet and red spinel in novelty and fashion jewellery). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating ruby, garnet and red spinel in novelty and fashion jewellery - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Red-Pink Opaque
| Colour | opaque coral, cherry and rose reds |
| Transparency | opaque |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Smooth even opaque red, usually moulded as coral-look beads or roses; too uniform for organic material. |
| Trade names | Bakelite (phenolic) • Catalin • lucite • acrylic |
| Misnomers | 'Coral' claims on fashion strands |
| Typical sizes | Beads, cameos, cabochons in bulk |
| Cutting styles | Moulded beads and components |
| Key separations | vs coral: coral shows growth texture under the loupe, effervesces in dilute acid, SG ~2.65 and is cool; plastic is bubble-marked, acid-proof, warm and light, and takes a hot point with an acrid smell. vs carnelian: chalcedony is 6.5-7 hard, waxy, banded. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (coral and carnelian - the classic fashion-jewellery swap). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating coral and carnelian - the classic fashion-jewellery swap - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Blue-Violet
| Colour | transparent blues and violets |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Bright even blue with plastic's soft, slightly greasy surface; moulded facets never quite crisp. |
| Trade names | acrylic • polystyrene (rhinestone-type) • resin |
| Misnomers | 'Sapphire' or 'tanzanite' claims on costume cards |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded brilliants, beads |
| Key separations | vs sapphire: hardness 9 vs 1.5-3, SG 4.0 vs ~1.2, DR vs isotropic, cool vs warm. vs aquamarine: beryl DR 1.577-1.583, SG 2.72, tube inclusions; plastic much lighter. vs tanzanite: trichroic DR vs isotropic plastic. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (sapphire, aquamarine, tanzanite and amethyst in fashion goods). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating sapphire, aquamarine, tanzanite and amethyst in fashion goods - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Blue-Violet Opaque
| Colour | opaque navy, lapis blue and turquoise tones |
| Transparency | opaque |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Flat even blue with a moulded gloss; copies of lapis sometimes include fake pyrite glitter. |
| Trade names | acrylic • reconstituted-stone lookalikes (marketing) |
| Misnomers | 'Lapis', 'reconstructed lapis' or 'synthetic lapis' claims |
| Typical sizes | Beads, cabochons, pendants in bulk |
| Cutting styles | Moulded beads and cabs |
| Key separations | vs lapis: natural lapis carries real pyrite crystals with metallic cleavage sparkle, calcite veins and SG 2.7-2.9; plastic has glitter flakes, bubbles, warm feel and ~1.2-1.5 SG (floats low or hangs in fresh water). vs turquoise: porosity, matrix texture, warm-water darkening; plastic inert. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (lapis lazuli, sodalite and turquoise). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating lapis lazuli, sodalite and turquoise - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Green
| Colour | transparent emerald, apple and sea greens |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Candy-green transparency with soft surfaces; often sold as 'jade-look' or emerald-style drops. |
| Trade names | acrylic • resin • 'jade-look' polymer |
| Misnomers | 'Emerald', 'jade' or 'green amethyst' claims |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded drops, beads, cabochons |
| Key separations | vs emerald: beryl hard (7.5-8), cool, DR with jardin; plastic warm, isotropic, soft. vs peridot: DR, doubling, SG 3.34. vs jade (even translucent jadeite/nephrite): jades are crystalline-interlocking with SG 2.95-3.33, take a waxy polish and resist a needle; plastic dents. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (emerald, peridot, green jade and tourmaline). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating emerald, peridot, green jade and tourmaline - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Green Opaque
| Colour | opaque spinach, jade and malachite greens |
| Transparency | opaque |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Dense even green, moulded smooth, sometimes with painted 'matrix' veining. |
| Trade names | acrylic • Bakelite (vintage greens) |
| Misnomers | 'Jade', 'malachite' or 'new jade' claims |
| Typical sizes | Bangles, beads, carvings in bulk |
| Cutting styles | Moulded bangles, beads, figurines |
| Key separations | vs jadeite/nephrite: mineral texture, SG 2.95-3.33, toughness, cool touch, waxy polish; plastic has mold seams, bubbles, warm feel, ~1.2-1.5 SG and dents under a needle. vs malachite: concentric natural banding (painted bands lack depth), effervescence in acid, SG 3.6. vs chrysoprase: chalcedony waxy, 6.5-7 hard. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (jade, malachite and chrysoprase). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating jade, malachite and chrysoprase - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Orange-Yellow
| Colour | transparent amber, honey and butterscotch yellows |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Convincingly amber-like warm yellow with swirled internal patterns; the surfaces betray it with soft polish. |
| Trade names | amberoid-style resin • 'Ambroid' (marketing) • polyester and epoxy resins |
| Misnomers | 'Amber', 'Baltic amber', 'copal' claims - the classic flea-market swap |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded beads, pendants, 'insect inclusions' cast in resin |
| Key separations | vs amber: amber floats in saturated saltwater (SG ~1.08), is warm, takes a static charge, burns with pine-resin scent, shows natural flow lines without bubbles; most plastics sink in saltwater, hot point smells acrid not resinous, and moulded 'insects' sit in perfect cavities. Copal (softer, younger resin) also smells resinous. vs citrine: quartz hard 7, DR, cool. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (amber above all - also citrine and honey jewellery). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating amber above all - also citrine and honey jewellery - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Orange-Yellow Opaque
| Colour | opaque butterscotch, mocha and ivory-tone yellows |
| Transparency | opaque |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Warm even opaque yellow, moulded as 'antique amber' or 'ivory' beads. |
| Trade names | acrylic • celluloid (vintage) |
| Misnomers | 'Amber', 'ivory' and 'bone' claims - some passed off as antique |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded beads, carved-look pendants |
| Key separations | vs amber: saltwater float, resin hot-point smell, static. vs bone/ivory: organic structure (canals, lamellae, Schreger lines in ivory) under the loupe; plastic is smooth with mold seams. vs vegetable ivory: cellular dotted structure, takes dye and scratches harder than plastic. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (amber, bone, ivory and vegetable ivory). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating amber, bone, ivory and vegetable ivory - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Colourless
| Colour | water-clear colourless |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Glassy-clear but soft and warm; facets are moulded, never crisp; a few products carry imitation play-of-colour foils. |
| Trade names | acrylic • lucite • plexiglass • 'Gemnuine'-type opal imitations |
| Misnomers | 'Diamond' claims on novelty rings; 'synthetic opal' for foil products |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded brilliants, beads, foiled 'opal' cabochons |
| Key separations | vs diamond: hardness 10 vs 1.5-3 (a needle digs), SG 3.52 vs ~1.2, diamond cold and crisp; plastic warm, greasy, moulded. vs rock crystal: quartz hard, DR, natural inclusions; plastic soft and isotropic. vs synthetic opal (foil type): real synthetic opal has silica structure at 2.0+ SG; plastic foil products dent with a needle and float. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (diamond and rock crystal in novelty goods; also colourless 'opal' imitations). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating diamond and rock crystal in novelty goods; also colourless 'opal' imitations - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — White
| Colour | opaque milky white |
| Transparency | opaque |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Flat chalky or waxy white, moulded smooth; sometimes coated with iridescent film to suggest pearl or opal. |
| Trade names | acrylic • celluloid • urethane |
| Misnomers | 'Opal', 'moonstone' or 'ivory' claims |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded beads, cabochons, pearl-style beads |
| Key separations | vs moonstone: feldspar DR with true rolling adularescence, hardness 6-6.5; plastic isotropic, soft. vs white opal: RI ~1.45, SG 2.15, porosity (sticks to tongue), possible play-of-colour; plastic ~1.2-1.5 SG, non-porous, dents. vs milk glass: glass is cold, heavy, vitreous; plastic warm, light, waxy. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (moonstone, white opal and ivory-look goods). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating moonstone, white opal and ivory-look goods - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Plastic — Grey-Black
| Colour | transparent jet black to smoky grey |
| Transparency | transparent |
| Clarity type | Flawless to bubbly - no clarity grading applies |
| Phenomena | Some products simulate play-of-colour, chatoyancy or iridescence |
| Appearance | Deep glossy black, moulded into mourning-style beads; lighter and warmer than jet. |
| Trade names | Bakelite (vintage black) • acrylic • epoxy |
| Misnomers | 'Jet', 'French jet' (which is actually glass) and 'black onyx' claims |
| Typical sizes | Any size in bulk |
| Cutting styles | Moulded beads, mourning-style pendants |
| Key separations | vs jet: jet is warm but light (SG ~1.3), burns with a coal-oil smell and shows organic grain; plastic is similarly light but moulded with seams and smells acrid on hot point. vs black onyx (dyed chalcedony): hard 6.5-7, waxy, cool, banded; plastic dents. vs obsidian: natural glass, conchoidal, cool, RI 1.48-1.52. Plastic separates from every gem material by: warm feel in the hand, very light heft (SG 1.05-1.55), softness (hardness 1.5-3 - a knife or needle digs in), gas bubbles and mold seams under the loupe, concave 'facets' with rounded junctions on molded stones, and a hot point that melts it with an acrid or carbolic smell (never use on customer goods). |
| Sources (localities) | Moulded by plastics factories worldwide; no natural source. |
| Availability | Plentiful in every colour at negligible cost. |
| Market notes | Costs cents per bead; sold honestly only when named plastic or by its polymer name - never as the stone it imitates (jet, black onyx and obsidian). |
| Care notes | Warm soapy water only; never ultrasonic or steam; keep away from solvents, perfume and heat. |
| In short | Moulded plastic imitating jet, black onyx and obsidian - exposed by heft, warmth, softness, bubbles and the hot-point reaction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.02 – $0.50 | costume component | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Sources
GIA gem encyclopedia · mindat.org · Wikipedia
Data compiled and fact-checked against gemmological literature, October 2026 (JDMIS gem reference). Properties are ranges accepted in gemmological practice; individual stones vary.
See also
Gemstone reference entries: gem #21 · gem #37 · gem #53 · gem #63 · gem #82 · gem #101 · gem #125 · gem #152
Related materials: Glass (gem imitation) · Hematine (Imitation Hematite)
Identification wizard · All 83 materials · Singapore gem labs