Citrine is the yellow to red-orange variety of crystalline quartz. This stone was once the Rodney Dangerfield of the gem world. Due to its abundance, it would “get no respect,” as it were. In recent decades this perception has changed, due in part to fashions that emphasize earth tones. Home shopping networks have been marketing the various shades of citrine aggressively with catchy adjectives like “butterscotch” and “whiskey.”
At the top end of the scale are prime specimens of the most saturated yellow, orange, and reddish tones. Those with less intense color fall into lower value ranges, with pale or smoky stones at the bottom. As with any gem material, custom cutting increases value. Inclusions decrease it. There is no exponential increase in value per carat with increase in size, as larger sizes are readily available. In many fancy cut or carved specimens, most of the value is due to the artistry of the cutting.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Is a Variety of||Quartz|
|Refractive Index||1.544 - 1.553|
|Colors||Yellow to Red-Orange|
|Fracture||Conchoidal, very brittle|
|Specific Gravity||2.651 (very constant)|
|Enhancements||Amethyst can be heat treated to change it to citrine. Not common. "Madeira" citrine with red flashes is a result of heat treatment.|
|Absorption Spectrum||Not diagnostic|
|Pleochroism||Very weak, different shades of yellow or orange.|
|Optics||o = 1.544; e = 1.553 (very constant). Uniaxial (+)|
|Etymology||From the old French citrin, meaning yellow.|
|Occurrence||Generally in pegmatites and veins. Found in geodes in alluvial deposits.|
|Inclusions||Natural quartz stones, including citrine, may have liquid, bread crumbs, zebra stripes, two and three phase inclusions, and negative crystals.|
Very little citrine is actually mined. The vast majority of citrine on the market is produced by heating smoky quartz (which produces light to medium yellows) and amethyst (which produces stronger yellows and orange-red to orangey brown shades). Natural stones tend to be pale yellow, often with smoky tones. Citrines range from light, lemon yellow to a rich, orange color with red flashes referred to as “Madeira.” (This refers strictly to a citrine color, not a locality, and is an accepted description. However, the use of the term “Madeira topaz” to refer to citrine is incorrect).
Citrine’s yellow colors are due to the presence of ferric iron. These colors have been traditionally associated with topaz. Confusion between these gemstones does occur, even though quartz and topaz are distinct gem species.
Citrine makes a fine jewelry stone. With no gemstone cleavage, a hardness of 7, stable colors in light, and no special care requirements, it can be used for any jewelry application. Like most quartz, it’s available in large sizes, so custom gem cutters can use this stone for dramatic and intricate cuts. This gem is a wonderful option for a large, beautiful stone for an engagement ring. Citrines can also be used for carvings.
Citrines can be grown hydrothermally in labs. Although natural quartz is common and inexpensive, synthetic quartz can be manufactured in sufficient quantities and at low cost, which makes the practice economically viable.
Turning natural smoky quartz and amethyst to citrine via heat treatment is usually done right at the mine. This is a stable treatment and is fully accepted within the gem trade. Colorless quartz stones have also been irradiated and heated to produce a neon, slightly greenish yellow color. These stones are called lemon quartz.
The prized “Madeira” color is created by heat treating citrine that possesses the proper iron content. Since there is no simple way of testing the iron content of citrine, this process must be monitored carefully.
Virtually all natural citrines come from Brazil.
Citrines in the thousands of carats are known. The Smithsonian Institution (Washington, D.C.) has Brazilian stones of 2,258, 1,180, 783, 278, 265, and 217 carats. Most large museums have similar baubles.
In the past, it was commonplace for citrine to be referred to by misleading names, such as “Brazilian topaz,” “Madeira topaz,” and even “topaz quartz.” Unscrupulous vendors can take advantage of the long association of yellow with topaz to pass off inexpensive citrines as more expensive topaz pieces. For more examples, consult our List of Misleading or False Gemstone Names.
See our Gemstone Care Guide for recommended cleaning methods.
by Dr. Joel Arem; Donald Clark, CSM IMG; Barbara Smigel, PhD GG