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CitrineVSYellow Glass
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Citrine, giving a numerical distinguishing point.
Note: properties whose numeric ranges do not overlap are auto-extracted. Both are measurable with a refractometer or heavy-liquid bath.
| Property | A: Citrine | B: Yellow Glass | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.544–1.553 | 1.480–1.700 | Overlap |
| Specific gravity (SG) | 2.64–2.66 | 2.30–4.50 | Overlap |
| Mohs hardness | 7.0 | 5.0–6.0 | A higher |
| Birefringence | 0.009 | — | — |
| Dispersion | — | — | — |
| Property | A: Citrine | B: Yellow Glass |
|---|---|---|
| Crystal system | 三方晶系 | 非晶質 |
| Pleochroism | 弱 | — |
| Chelsea filter | inert | — |
| UV (long-wave) | inert | — |
| UV (short-wave) | inert | weak (yellow) |
◆Citrine (SiO₂ quartz colored yellow by Fe³⁺-substituted iron in tetrahedral sites, Mohs 7, SG 2.65, RI 1.544–1.553, doubly refractive, 0.013) is the natural species that yellow glass most often imitates. Refractometer reads 1.544–1.553 for citrine versus 1.50–1.70 for glass (overlap requires combined testing). The decisive separation comes from polariscope examination (citrine doubly refractive, glass singly refractive) and from nclusions, and characteristic 'phantom' growth surfaces; glass shows regular round gas bubbles and pressing-die seams). Mohs 7 citrine is unaffected by a steel-knife scratch test that easily marks Mohs 5–6 glass. Note: the bulk of commercial 'citrine' is heat-treated amethyst from Brazilian Minas Gerais (notably the Marabá deposit), produced by heating purple amethyst to 450–500°C to convert Fe⁴⁺ chromophore to Fe³⁺ yellow — this is fully natural quartz with disclosed , distinct from glass imitations. Genuine natural unheated citrine is rare (principally from Madagascar and Ural Mountains) and commands a 3–10× premium. Uranium glass shows the diagnostic strong green LW-UV — natural citrine is inert or only weakly fluorescent. Disclosure as 'glass' or 'imitation citrine' is required under FTC Jewelry Guides §23.25.
Distinguishing tools
Tools that decide between Citrine and Yellow Glass in practice.
Note: this page is auto-generated from published GIA / CGL reference values. Individual stones, treatments, and synthetics may fall outside these ranges. For a definitive identification, consult an accredited gem laboratory.