Citrine

Yellow variety of Quartz
Quartz is the reference stone for hardness 7 on Mohs´ scale of hardness

Citrine shop
Synonyms and trade names: Golden Topaz, Madeira Topaz
Thank goodness these misleading terms, which were accepted trade names, are only rarely encountered today (and should be abandoned altogether).

Can be confused with: all yellow gemstones

Localities: natural Citrine is quite rare. The colour is mostly rather pale, often with a slightly brownish (smoky) tinge. The most important deposits are in Brazil and Russia.

naturfärbiger citrin - natural citrine   naturfärbiger citrin - natural citrine
Two naturally coloured Citrines from Brazil

Most Citrines offered by the gem trade are heat-treated Amethysts or heat-treated Smoky Quartz.The colours of treated Citrines are in general more intense and more attractive than those of natural Citrines.
The procedure is legitimate, accepted by the CIBJO and must be disclosed at the point of sale.

Colour: from pale yellow to orange. For yellowish orange stones of lighter tone the trade name Palmyra Citrine has taken hold. Deep orange stones, sometimes with a reddish or slightly brownish tinge, are called Madeira Citrines.


citrin (gebrannter Amethyst) - citrine (heat-treated amethyst)  citrin (gebrannter Amethyst) - citrine (heat-treated amethyst)
Two Citrines (heat-treated)

madeiracitrin - madeira citrine
Madeira Citrine (heat-treated)

Palmyra citrin - Palmyra citrine  Palmyra citrin - Palmyra citrine
Two Palmyra Citrines (heat-treated) in concave cut and conventional cut

Handling: Citrine is sensitive to heat.. Be careful during soldering as colour change can occur at relatively low temperatures.
Sensitive to hydrofluoric acid only.

Citrine has no or only very weak cleavage and thus is unproblematic during setting.

 

Worth knowing: Quartz crystals often sport distinct colour zoning which poses a challenge to the gemcutter. In skilfully facetted stones the zoning is only visible when viewed from the side. When viewed from the top, colour should appear distributed evenly. In most cases zoning will be nearly to completely invisible in a bezel setting.

 

farbzonierung - colour zoning

Distinct colour zoning, clearly visible in a cabochon

Attention: the market is flooded with synthetic Citrines which are very hard to identify. Be particularly alert with intensely coloured eyeclean stones. The presence of colour zoning is not (any more) proof of natural origin.
synthetic citrine - citrinsynthesehydrothermaler synthetischer quarz, hydrothermally produced synthetic quartz
Hydrothermally produced synthetic Citrine
The rough piece contains a remnant of the seed crystals suspension wire

We buy eyeclean stones only from reliable suppliers - well, actually we, of course, buy all our stones from reliable sources only ;-) - and only if we get a chance to inspect the rough material ourselves. No matter if we order from a factory or give our own rough for cutting, our local agents monitor the whole cutting process.

Citrine shop

 

Gemmological Properties of Citrine

Formula:
SiO2
Crystal system:
trigonal
Mohs hardness:
7 (reference stone)
Specific gravity:
2.65
Refractive index:
birefringent 1.543-1.554
Max. Birefringence:
0.009
Dispersion:
0.013
Pleochroism:
natural: weak, pale yellow / yellow, heat-treated: mostly none
Luminiscence:
inert
Lustre:
vitreous
Cleavage:
weak
Fracture:
conchoidal
Colour:
pale yellow to orange