How to tell if citrine is real
Real citrine is yellow quartz, hardness 7, refractive index 1.544 to 1.553, unlike topaz. GIA says most citrine sold is heated amethyst; no home test sees it.
To tell if citrine is real, ask two questions. Is it quartz? Hardness 7, refractometer readings of 1.544 and 1.553, and a 20.00 g piece weighing 12.45 g in water say yes. Is the colour natural? GIA says most citrine on the market is heat-treated amethyst, and no home test answers that.
In short
- Real citrine is quartz. GIA calls it the transparent, pale yellow to brownish orange variety of quartz, coloured by a trace of iron, with refractive index 1.544 to 1.553 and hardness 7. Citrine has no row on the September 2026 IMA list; quartz does. A yellow stone that is not quartz is not citrine, whatever the label says.
- The two-question rule. Is it quartz, and was the colour made by nature? The first is answerable at home with a lens, a scale and a refractometer. The second is not: GIA says natural citrine is rare and most citrine on the market comes from heat-treating amethyst, and gives no home test for it.
- A documented negative from GIA’s journal. Kurt Nassau, in Gems & Gemology in 1981, concluded that there were no known tests to tell natural amethyst-citrine heated or irradiated in nature from amethyst treated by man, or from the synthetic equivalent. That is the most recent statement on the question among the sources fetched for this page.
- Citrine geodes and cathedrals are usually heated amethyst, on GIA’s account: giant amethyst geodes from areas like Brazil are often heated to become citrine cathedrals. That makes the specimen quartz, and real; it does not make the colour natural.
- Topaz is the old confusion, and weight separates it. A 20.00 g piece reads 12.45 g in water as quartz and 14.27 to 14.40 g as topaz. On a cut stone the gap shrinks with size: 0.182 g at 10 ct, 0.018 g at 1 ct, worked. The International Gem Society calls “topaz quartz” a misnomer for citrine.
| Label or material | What it is, per the source | Hardness | Refractometer | 20.00 g piece in water | Question 1: is it quartz? | Question 2: was the colour natural? |
|---|---|---|---|---|---|---|
| Citrine, natural colour | Yellow to orange quartz; rare (GIA) | 7 | 1.544 and 1.553 | 12.45 g | Yes, at home | No home test; GIA gives none |
| Citrine from heated amethyst | Most citrine on the market (GIA) | 7 | 1.544 and 1.553 | 12.45 g | Yes, at home | No home test; GIA gives none |
| Citrine cathedral or geode | Giant amethyst geodes often heated (GIA) | 7 | Not practical on a geode | Matrix spoils it | Yes: crystal form and lens | GIA: often heated; assume so unless documented |
| Ametrine (amethyst-citrine) | Both colours in one crystal; Bolivia (GIA) | 7 | 1.544 and 1.553 | 12.45 g | Yes, at home | Nassau 1981: no known test |
| Madeira citrine | Strong orange, from heat-treating citrine (IGS) | 7 | 1.544 and 1.553 | 12.45 g | Yes, at home | Heated, by the IGS definition |
| Synthetic yellow quartz | Laboratory quartz (IGS; Nassau) | 7 | 1.544 and 1.553 | 12.45 g | Yes: it is quartz | Not natural; laboratory question |
| Yellow or precious topaz | Separate species, Al2SiO4(F,OH)2 (sheet; GIA) | 8 | 1.606 to 1.644 (sheet) | 14.27 to 14.40 g | No: decided at home | Not applicable |
| Yellow glass | Imitation (IGS glass article) | 5 to 6 | One reading, 1.470 to 1.700 | 11.30 to 15.56 g | No: refractometer, not scale | Not applicable |
How to tell if citrine is real: the steps, in order
Start with a 10x lens and a lamp; finish, if you must, at a gem laboratory. Each step costs more, or risks more, than the one before. The Handbook of Mineralogy quartz sheet gives the numbers: SiO2, hardness 7, density 2.65, indices 1.544 and 1.553, cleavage rarely observable, fracture conchoidal. Day one needs a lens, a scale reading to 0.01 g with a thread to suspend the piece, and, for a cut stone, access to a refractometer.
- Lens. The International Gem Society says glass usually shows swirl marks and round bubbles. A crystal on its matrix, with growth faces intact, is the strongest evidence of quartz at this stage.
- Scale. Weigh in air and suspended in water. A 20.00 g quartz piece reads 12.45 g; GIA’s 2.66 (+0.03/−0.02) gives 12.42 to 12.57 g. Topaz reads 14.27 g or more. The method is on how to measure specific gravity at home.
- Hardness, on rough or a hidden spot only. Quartz is 7, glass 5 to 6. Never on a faceted stone; see how to test mineral hardness properly.
- Refractometer. Two readings, 1.544 and 1.553, mean quartz. One reading means it is not quartz. The glass detail is on how to tell if amethyst is real, which uses the same quartz numbers.
- Stop, or go to a laboratory. After step 4 the species question is settled. The colour question is not, and GIA gives no home test for it.
The finish state is one of four labels: citrine (quartz, colour origin unknown); citrine, heated (only with documentation); not quartz, named (topaz, glass); or untested. Dyed material is a separate check, on how to tell if a crystal is dyed. The identification pages are indexed at the collecting guides.
Is my citrine real or heated amethyst? What GIA says
Heated amethyst is real citrine in the species sense: it is quartz, and GIA counts it as the bulk of citrine on the market. The GIA citrine page says natural citrine is rare and that most citrine on the market is the result of heat treatment of amethyst. The GIA citrine description adds that heat treatment changes some amethyst from pale violet to yellow, and that the original hue can decide how rich the yellow becomes. Its example is an amethyst turned orangy citrine by low-temperature heat treatment.
Can a test tell them apart? On the published record fetched for this page, no. Nassau, Gems & Gemology, Spring 1981, in GIA’s journal, described heating and irradiation experiments on natural amethyst-citrine quartz and on amethyst, and concluded that there were presently no known tests to distinguish material heated or irradiated in nature from amethyst treated by man, or from synthetic equivalents. The paper is from 1981 and concerns bicoloured material; we found no later GIA statement giving a home method, and this page gives none. Treat this as a documented negative.
What that means for a geode. GIA says giant hollow amethyst geodes from areas like Brazil are often heated to become citrine cathedrals. A citrine cathedral is therefore quartz, and real, but the colour is most likely made, in our judgement, unless its history is documented. No heat or flame test appears on this site: heat is how amethyst changes colour, as why is my amethyst losing color sets out from its own sources.
Citrine or topaz? The weight gap, worked by carat
Citrine and topaz were confused before modern gemmology, GIA says, because of citrine’s tawny colour. The International Gem Society quartz article lists “topaz” and “topaz quartz” as misnomers for citrine. They are separate species: quartz SiO2, hardness 7, density 2.65; topaz Al2SiO4(F,OH)2, hardness 8, density 3.49 to 3.57, on their Handbook sheets.
Worked, in water. A 20.00 g piece reads 12.45 g as quartz and 14.27 to 14.40 g as topaz, a gap of at least 1.82 g; the topaz page calls 14.27 g its floor. Cut stones are smaller, so scale the gap: at 0.200 g per carat, a 20 ct stone (4.00 g) reads 2.491 g as quartz and 2.854 to 2.880 g as topaz, a gap of 0.363 g. At 10 ct the gap is 0.182 g; at 5 ct, 0.091 g; at 1 ct, 0.018 g.
Where the scale stops. A 1 ct gap of 0.018 g is under two counts of a scale reading to 0.01 g, so for small stones the refractometer decides: topaz reads 1.606 to 1.644 on its sheet, well above quartz’s 1.553. Smoky quartz carries the same confusion; the gem society calls “Madeira topaz” a misnomer for it. The topaz side is on topaz; quartz on quartz.
Fake citrine: glass, synthetic quartz and dye
Glass fails at the refractometer, not on the scale. The International Gem Society glass article gives glass a single refractive index between 1.470 and 1.700, hardness 5 to 6 and specific gravity 2.30 to 4.50, so a 20.00 g piece reads anywhere from 11.30 to 15.56 g in water, either side of quartz’s 12.45 g. Weighing alone cannot clear glass; the lens and the refractometer can.
Synthetic quartz passes the home tests on this page. The gem society says synthetic quartz comes in every colour, and Nassau names synthetic amethyst-citrine among the materials he could not separate by test in 1981. A synthetic stone is quartz, with quartz’s numbers; origin is a laboratory question, as it is for amethyst.
Dye is different from heat. Colour concentrated along cracks under a lens is the warning sign set out on how to tell if a crystal is dyed; general imitations are on how to tell if a crystal is fake. This page gives no buying advice. Nothing on this site is offered for sale; the wanted list is the only commercial route.