Key properties
| Chemical formula | Amorphous silica (SiO2) melt with fluxes, stabilisers and colourants; high-lead 'strass' variants for brilliancy |
| Crystal system | Amorphous |
| Mohs hardness | 5-6 |
| Toughness | Poor to fair - brittle |
| Refractive index | 1.470-1.700 |
| Optic character | Single refractive; strong anomalous double refraction common from strain |
| Specific gravity | 2.30-4.50 |
| Cleavage | None |
| Fracture | Conchoidal; splintery or granular in cat's-eye and goldstone imitations |
| Habit | Molded, pressed, cast or cut from blocks; foil-backed as rhinestones/chatons |
| Lustre | Vitreous; polish: Vitreous |
| UV fluorescence | Variable with colourants - inert, greenish (uranium glass glows strong green), orange or bluish reactions all occur. |
| Pleochroism | None. |
| Cause of colour | Transition-metal and rare-earth oxides (cobalt blue, chromium green, iron green-yellow, manganese violet, copper and gold colloids for red), cadmium-sulfur yellows, uranium greens; metallic copper flakes for aventurescent goldstone. |
| Typical inclusions | Round gas bubbles, swirl flow lines, surface cavities; molded stones show mold seams, orange-peel skin, concave facets and rounded junctions |
| Stability | Attacked by acids, acid fumes and prolonged humidity; old lead glass devitrifies or 'crizzles'; foils darken with water. |
| Heat sensitivity | High - softens under a torch and cracks with thermal shock. |
| Care and cleaning | Warm soapy water; avoid ultrasonic and steam especially for coated, foil-backed or assembled pieces. |
| Availability | Plentiful in every colour, shape and size at negligible cost. |
| Recognition | Universal - the imitation every jeweller must be able to spot cold. |
Varieties (11)
Glass — Red-Pink
| Colour | transparent reds and pinks from cranberry to deep ruby |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Bright even red with glassy shine; old strass versions have a soft richness, modern molded beads look uniformly perfect. |
| Trade names | paste • strass (high-lead) • gold-ruby glass |
| Misnomers | 'Bohemian ruby' or 'ruby glass' sold as gem ruby; 'synthetic garnet' claims |
| Typical sizes | Any size, calibrated by the thousand |
| Cutting styles | Molded beads, molded cabochons, faceted paste |
| Key separations | vs ruby: ruby is DR at 1.762-1.777 with silk and Cr fluorescence, SG about 4.0; red glass is SR around 1.5-1.7 with bubbles and SG usually 2.4-3.0. vs almandite garnet: garnet SR but 1.79 RI, natural inclusion trails, SG 3.95-4.2. vs rubellite: tourmaline DR 1.62-1.64, strong dichroism. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (ruby, red spinel, garnet and rubellite). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating ruby, red spinel, garnet and rubellite - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Red-Pink Opaque
| Colour | opaque brick red to coral pink |
| Transparency | opaque |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Dead-even opaque red, often molded as coral-look beads or cameos; too uniform to be organic. |
| Trade names | coral glass • oxyblood glass (trade slang) |
| Misnomers | 'Red coral' claims on fashion strands |
| Typical sizes | Bead strands by the metre |
| Cutting styles | Molded beads, cameos, intaglios, cabochons |
| Key separations | vs coral: real coral shows growth structure (grain, ridges, pore pattern) under the loupe, effervesces in dilute hydrochloric acid, SG about 2.65; glass is bubble-marked and acid-proof. vs carnelian: chalcedony is 6.5-7 hard with waxy lustre and natural banding, SG 2.60. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (coral and carnelian). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating coral and carnelian - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Blue-Violet
| Colour | transparent blues and violets from sky blue to cobalt and amethystine purple |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Vivid, perfectly even blue with the slightly fat look of molded glass; old cobalt strass has real charm. |
| Trade names | paste • strass • cobalt glass |
| Misnomers | 'Sapphire glass' (a watch-crystal term that confuses shoppers) and outright 'sapphire' claims |
| Typical sizes | Any size in bulk |
| Cutting styles | Faceted paste, molded beads, pressed cabochons |
| Key separations | vs sapphire: sapphire DR 1.762-1.778, SG about 4.0, silk; glass SR ~1.5-1.7, bubbles. vs aquamarine: dangerously close on RI - separate with the polariscope (aquamarine DR 1.577-1.583, elongated two-phase tubes) and SG 2.72 vs glass ~2.4-2.6. Cobalt glass flashes red under the Chelsea colour filter - aquamarine and sapphire do not. vs tanzanite: tanzanite DR with strong trichroism. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (sapphire, aquamarine, blue topaz, tanzanite and amethyst). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating sapphire, aquamarine, blue topaz, tanzanite and amethyst - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Blue-Violet Opaque
| Colour | opaque navy, lapis blue and turquoise-blue |
| Transparency | opaque |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Smooth flat opaque blue with a glassy skin, sometimes flecked with gold-leaf imitating pyrite. |
| Trade names | lapis glass • Belgian lapis (marketing) |
| Misnomers | 'Lapis' or 'synthetic lapis' claims - glass is not lapis in any sense |
| Typical sizes | Bead strands and cabs in bulk |
| Cutting styles | Beads, cabochons, carved pendants |
| Key separations | vs lapis lazuli: natural lapis shows pyrite crystals with metallic sparkle and calcite veins, SG 2.7-2.9, hardness 5-5.5; glass has bubble trails, uniform opacifier, no real pyrite (gold leaf sits in a surface layer) and takes a higher polish. vs sodalite: sodalite's violet-white patches and SG 2.2-2.3. vs turquoise: turquoise SG 2.4-2.9 with matrix and porosity; glass stays inert. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (lapis lazuli, sodalite and turquoise). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating lapis lazuli, sodalite and turquoise - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Green
| Colour | transparent greens from yellowish sea green to emerald-like bluish green |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Fresh even green, glassy and bright; uranium 'vaseline' glass glows eerily green under UV. |
| Trade names | paste • strass • vaseline/uranium glass (antique) |
| Misnomers | 'Emerald glass' sold as emerald; 'Brazilian emerald' on old paste |
| Typical sizes | Any size in bulk |
| Cutting styles | Faceted paste, molded cabochons, beads |
| Key separations | vs emerald: emerald DR 1.577-1.583 with jardin inclusions, SG 2.72; glass SR with bubbles. vs peridot: peridot DR 1.65-1.69 with strong doubling and lily-pad inclusions, SG 3.34. vs chrome tourmaline: DR 1.62-1.64, SG 3.06. Uranium glass announces itself under UV. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (emerald, peridot, green tourmaline and tsavorite). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating emerald, peridot, green tourmaline and tsavorite - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Green Opaque
| Colour | opaque spinach, jade and apple greens |
| Transparency | opaque |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Dense even green with vitreous skin, often molded as jade-style bangles or beads; lacks any fibrous texture. |
| Trade names | jade glass (trade slang) |
| Misnomers | 'Jade', 'jadeite' or 'new jade' claims on fashion bangles |
| Typical sizes | Beads and bangle blanks in bulk |
| Cutting styles | Molded bangles, beads, cabochons, carvings |
| Key separations | vs jadeite/nephrite: jades show fibrous or granular interlocking texture under magnification, are tough rather than brittle, and measure SG 2.95 (nephrite) to 3.33 (jadeite) vs milk glass ~2.4-2.6; glass bangles snap where jade bends. vs malachite: malachite's concentric banding, SG 3.6 and effervescence in acid. vs chrysoprase: chalcedony waxy lustre, SG 2.6, hardness 6.5-7. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (jade, malachite and chrysoprase). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating jade, malachite and chrysoprase - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Orange-Yellow
| Colour | transparent golden yellow to orange |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Warm, glowing amber-toned yellow, often in molded or pressed vintage beads. |
| Trade names | paste • strass • canary glass |
| Misnomers | 'Citrine' or 'topaz' on fashion jewellery cards |
| Typical sizes | Any size in bulk |
| Cutting styles | Molded beads, faceted paste, pressed stones |
| Key separations | vs citrine: quartz DR 1.544-1.553 with natural inclusions, hardness 7; glass SR ~1.5-1.7 with bubbles and 5-6 hardness. vs topaz: DR 1.61-1.64, SG 3.53, cleavage-plane sheen. vs yellow sapphire: DR 1.762-1.778. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (citrine, golden topaz, yellow sapphire and heliodor). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating citrine, golden topaz, yellow sapphire and heliodor - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Orange-Yellow Opaque
| Colour | opaque butterscotch, honey and amber-toned yellow |
| Transparency | opaque |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Smooth opaque honey colour, warm and even, molded into amber-look beads. |
| Trade names | amber glass • butterscotch glass |
| Misnomers | 'Amber', 'Baltic amber' and 'pressed amber' claims (pressed amber is real amber; glass is not) |
| Typical sizes | Bead strands in bulk |
| Cutting styles | Molded beads, pendants, cabochons |
| Key separations | vs amber: amber floats or hangs low in saturated saltwater (SG ~1.08), is warm to the touch, burns with a pine-resin smell and shows swirls without bubbles; glass sinks fast, stays cool and bubbles. Hot point: amber gives resin smell, glass will not melt at hot-point temperature. vs bone/ivory: organic structure lines visible under the loupe. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (amber, bone and ivory). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating amber, bone and ivory - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Colourless (paste)
| Colour | water-clear colourless |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Clean and bright but lacking diamond's crisp light return; old paste was foil-backed to fake brilliance. |
| Trade names | paste • rhinestone (foil-backed) • strass • crystal (lead-glass marketing) |
| Misnomers | 'Crystal' implying gem crystal (glass is amorphous); 'diamond' in 'Austrian diamond' marketing |
| Typical sizes | Melee to large plaques in bulk |
| Cutting styles | Faceted brilliants (often foil-backed), molded stones |
| Key separations | vs diamond: thermal tester (glass fails), fire (diamond 0.044 vs glass typically ~0.01-0.02), SG (diamond 3.52; glass usually ~2.4-2.6), and loupe - bubbles, mold seams, worn facet junctions, concave facets. vs rock crystal: quartz DR 0.009, hardness 7, natural inclusions; glass SR with bubbles. vs zircon: strong doubling and high RI. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (diamond, rock crystal, colourless topaz and zircon). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating diamond, rock crystal, colourless topaz and zircon - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — White (milk)
| Colour | opaque milky white, sometimes with opalescent blue edge-glow |
| Transparency | opaque |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Chalky smooth white with a soft glow at edges in opalescent grades; feels cool and vitreous. |
| Trade names | milk glass • opaline glass • opalescent glass |
| Misnomers | 'Opal' or 'moonstone' claims on fashion beads |
| Typical sizes | Beads and cabs in bulk |
| Cutting styles | Molded beads, cabochons, cameos |
| Key separations | vs moonstone: moonstone is DR feldspar (1.52-1.54) with true adularescence and cleavage; milk glass is SR with flat dead white unless iridised. vs white opal: opal SG 2.15, RI ~1.45, may show play-of-colour, porous; glass SG ~2.4-2.6, vitreous skin. vs white chalcedony: waxy lustre, hardness 6.5-7. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (moonstone, white opal and white chalcedony). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating moonstone, white opal and white chalcedony - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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.
Glass — Grey-Black
| Colour | transparent jet black to smoky grey |
| Transparency | transparent |
| Clarity type | Flawless to heavily bubbled - glass knows no clarity grading |
| Phenomena | Aventurescence in glitter (goldstone) types; colour-change in rare doped glass |
| Appearance | Deep mirror-black, usually molded; looks like onyx or jet until louped. |
| Trade names | black glass • French jet (Victorian) |
| Misnomers | 'French jet' honestly means black glass but is resold loosely as jet; 'black onyx' claims |
| Typical sizes | Bead strands in bulk |
| Cutting styles | Molded beads, mourning-style jewellery, cabochons |
| Key separations | vs onyx: dyed chalcedony is 6.5-7 hard with waxy lustre and even bands; glass 5-6 with vitreous skin and bubbles. vs obsidian: a natural glass - RI 1.48-1.52, conchoidal, may carry crystallites; black imitation glass is often higher RI. vs jet: jet is warm, SG 1.3, burns with a coal smell; glass sinks and is cold. Glass separates from any crystalline gem by a combination of round gas bubbles and swirl flow lines under the loupe, mold seams or an orange-peel skin on molded stones, concave facets and rounded facet junctions, single refraction (often with strong strain ADR), a warm feel in the hand, and hardness only 5-6 (a steel point scratches it). |
| Sources (localities) | Made by glassworks worldwide; no natural source. |
| Availability | Plentiful in every colour and size, always. |
| Market notes | Costs cents per stone; the ethical duty is naming it as glass, never as the stone it imitates (black onyx, obsidian, jet and melanite garnet). |
| Care notes | Warm soapy water; avoid ultrasonic and steam for foil-backed, coated or assembled pieces. |
| In short | Man-made glass imitating black onyx, obsidian, jet and melanite garnet - identified by bubbles, swirls, mold seams, low hardness and single refraction. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–10.00 | $0.05 – $1.00 | 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 #20 · gem #36 · gem #52 · gem #62 · gem #81 · gem #100 · gem #124 · gem #151
Related materials: Hematine (Imitation Hematite) · Plastic (gem imitation)
Identification wizard · All 83 materials · Singapore gem labs