Gem library
Citrine
The merchants' solar quartz
Citrine is yellow to orange quartz, the stone merchants slipped into their cash box to attract prosperity. A little-known fact: nearly all citrine sold today is heated Brazilian amethyst — a stable, ancient and entirely accepted treatment.
- Hardness (Mohs)
- 7
- Density
- 2.63 – 2.65
- Crystal system
- Trigonal
- Refractive index
- 1.544 – 1.553
- Cleavage
- None
Mineralogical identity
- Family
- Quartz — silica group
- Species
- Quartz
- Variety
- Citrine
- Chemical formula
- SiO₂
- Crystal system
- Trigonal (rhombohedral)
- Classification
- Semi-precious stone
- Rarity
- Common
- Indicative price
- €2 – 30/ct
Etymology
From the Latin citrus, the lemon, for its yellow colour.
Physical & optical properties
- Hardness (Mohs)
- 7
- Density
- 2.63 – 2.65
- Refractive index
- 1.544 – 1.553
- Birefringence
- 0.009
- Cleavage
- None
- Fracture
- Conchoidal
- Lustre
- Vitreous
- Diaphaneity
- Transparent
- UV fluorescence
- None
- Pleochroism
- Weak
- Colours
- yellow, orange, honey
Formation, geology & history
Natural or heated?
Natural citrine exists, but it is rare and its tone usually stays pale straw yellow. The intense orange, «madeira» and reddish-brown shades of the trade almost always come from amethyst or smoky quartz heated between 400 and 560 °C. The treatment is irreversible, stable, and alters neither hardness nor durability. A reliable clue: heated citrines often show banded zoning inherited from the original amethyst, and a slightly reddish tinge at the base of the crystals where colour was most concentrated.
Formation and deposits
Like all quartz varieties, citrine crystallises in hydrothermal cavities and pegmatites. Its natural colour comes from traces of interstitial iron — a different mechanism from amethyst, where iron occupies a substitutional site. Brazil dominates the market, particularly Rio Grande do Sul where the amethyst kilns run continuously. Bolivia supplies ametrine, an extraordinary bicolour violet-and-gold quartz from a single deposit worldwide, in which nature itself partly heated the crystal.
Use in jewellery
Hardness 7, no cleavage and a modest price make citrine ideal for spectacular large cuts: stones of 20 to 50 carats are common, which would be unthinkable for a sapphire. It suits yellow gold perfectly and lends itself to fantasy cuts. Its only weakness: it fades under prolonged sun, which makes it better suited to evening rings than to everyday outdoor wear.
How to recognise it
- Cool to the touchLike all quartz, citrine stays cool for several seconds against the cheek, where glass or resin warm almost instantly.
- Colour zoningA gradient from pale yellow towards orange, or bands visible against the light, indicates true quartz. A flat, uniform orange suggests glass.
- Scratches glassHardness 7: it marks a bottle without difficulty. Orange calcite, often sold as citrine, is scratched by a knife.
Imitations, treatments & confusions
- Cast glassRound bubbles, rounded facet mouldings, lighter for the same volume. The breath test: mist clears faster on glass than on quartz.
- Dyed calcite or aragoniteHardness 3 only. A knife scratch test, or a drop of vinegar (effervescence on calcite), settles it immediately.
- Undeclared heated amethystNot a fake, but the information belongs on the label. Certified natural citrine is worth appreciably more.
Deposits & origins
Brazil (Rio Grande do Sul, where amethyst is heated), Bolivia (ametrine from the Anahí mine), Madagascar, Spain, Russia, Zambia; untreated natural citrine is markedly rarer
Care & precautions
- Warm water, mild soap, a soft toothbrush. Rinse and dry at once.
- Keep out of sunlight: citrine fades and, if overheated, can turn colourless or milky.
- Ultrasonic cleaning is acceptable on sound stones, but avoid hot steam.
- It scratches glass and is scratched by topaz: store individually in a pouch.
Traditions & crystal healing
- Chakras
- Solar plexus · sacral
- Zodiac signs
- Leo · Gemini
- Element
- Fire
- Month
- November
Nicknamed «the merchant's stone», tradition holds that it attracts abundance and material success. It is also credited with infectious joy, self-confidence and energy on difficult mornings. A quirk of the tradition: it is said to be one of the few stones that never absorbs negativity and therefore needs no cleansing.
The virtues described here belong to tradition and cultural heritage. They are in no way medical advice and never replace a consultation.
Frequently asked questions
Is my citrine heated?
Statistically yes: more than 95 % of the market. Clues: a strong orange tone, banded zoning, a faint reddish reflection. Pale yellow citrine is more likely natural.
Citrine or imperial topaz?
Imperial topaz is harder (8), denser (3.5 against 2.65) and has a clean basal cleavage. It is also worth twenty to fifty times more per carat.
Can it be worn every day?
Yes for hardness, with one caveat: avoid prolonged sun exposure. A citrine ring worn daily in bright sun will fade over a few years.