The Quartz Family
Crystalline quartz and chalcedony: from the purple of amethyst to the green of nickel in chrysoprase.
Each gem in four tones: the hue it is named by, its light part, its deepest part and the sparkle where light bounces off the facets. The colors are our own approximations, not laboratory standards.
Amethyst
Quartz colored by iron and radiation
Purple quartz, from a light lilac to a deep, intense purple. Its color comes from iron (Fe3+) that natural radiation turns into Fe4+.
Heat can lighten very dark amethyst; heated, some amethyst turns yellow, and that is where most of the citrine on the market comes from.
Amethyst · hue
The main hue, the color the gem is named by.
Material: Amethyst, faceted, hue
RGB(138, 79, 179)
Amethyst · light
The light part, where the stone is thinnest or light passes straight through.
Material: Amethyst, faceted, light
RGB(184, 138, 214)
Amethyst · deep
The deepest part, in the facets in shadow.
Material: Amethyst, faceted, deep
RGB(91, 42, 128)
Amethyst · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Amethyst, faceted, sparkle
RGB(213, 184, 234)
Citrine
Quartz, mostly heated amethyst
The transparent, pale yellow to brownish orange variety of quartz. Natural citrine is rare.
Most of the citrine on the market is heated amethyst. Before modern gemology, its tawny color led to confusion with topaz.
Citrine · hue
The main hue, the color the gem is named by.
Material: Citrine, faceted, hue
RGB(232, 169, 58)
Citrine · light
The light part, where the stone is thinnest or light passes straight through.
Material: Citrine, faceted, light
RGB(242, 200, 112)
Citrine · deep
The deepest part, in the facets in shadow.
Material: Citrine, faceted, deep
RGB(192, 126, 26)
Citrine · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Citrine, faceted, sparkle
RGB(248, 221, 160)
Ametrine
Bicolored quartz
Quartz with the colors of both amethyst and citrine in the same stone; it is also called amethyst-citrine.
Here its purple is the hue and the deep part, and its yellow the light part and the sparkle. According to CIBJO, it is rarely heated.
Ametrine · hue
The main hue, the color the gem is named by.
Material: Ametrine, faceted, hue
RGB(154, 95, 176)
Ametrine · light
The light part, where the stone is thinnest or light passes straight through.
Material: Ametrine, faceted, light
RGB(240, 192, 96)
Ametrine · deep
The deepest part, in the facets in shadow.
Material: Ametrine, faceted, deep
RGB(106, 58, 133)
Ametrine · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Ametrine, faceted, sparkle
RGB(247, 221, 160)
Smoky quartz
Quartz colored by aluminum and radiation
Aluminum replaces part of the silicon in the quartz; over geological time, natural radiation removes an electron from a neighboring oxygen and creates the smoky color.
With intense radiation and enough aluminum, the quartz turns black; heated, the color goes and it is colorless again. According to CIBJO, it is commonly irradiated.
Smoky quartz · hue
The main hue, the color the gem is named by.
Material: Smoky quartz, faceted, hue
RGB(122, 98, 80)
Smoky quartz · light
The light part, where the stone is thinnest or light passes straight through.
Material: Smoky quartz, faceted, light
RGB(166, 141, 120)
Smoky quartz · deep
The deepest part, in the facets in shadow.
Material: Smoky quartz, faceted, deep
RGB(74, 58, 46)
Smoky quartz · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Smoky quartz, faceted, sparkle
RGB(201, 184, 168)
Rose quartz
Quartz with pink nanofibers
Its pink does not come from the quartz itself but from tiny pink fibers, 0.1 to 0.5 microns wide, inside it: that was the conclusion of a study of 29 deposits around the world (American Mineralogist, 2001).
The fibers owe their pink to a charge transfer between iron and titanium. According to CIBJO, rose quartz is never treated.
Rose quartz · hue
The main hue, the color the gem is named by.
Material: Rose quartz, faceted, hue
RGB(240, 184, 196)
Rose quartz · light
The light part, where the stone is thinnest or light passes straight through.
Material: Rose quartz, faceted, light
RGB(247, 214, 221)
Rose quartz · deep
The deepest part, in the facets in shadow.
Material: Rose quartz, faceted, deep
RGB(217, 143, 160)
Rose quartz · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Rose quartz, faceted, sparkle
RGB(251, 232, 236)
Prasiolite
Green quartz
Green quartz. According to CIBJO, it is commonly heated.
For the US Federal Trade Commission, calling it a «green amethyst» may be misleading.
Prasiolite · hue
The main hue, the color the gem is named by.
Material: Prasiolite, faceted, hue
RGB(169, 196, 138)
Prasiolite · light
The light part, where the stone is thinnest or light passes straight through.
Material: Prasiolite, faceted, light
RGB(201, 220, 178)
Prasiolite · deep
The deepest part, in the facets in shadow.
Material: Prasiolite, faceted, deep
RGB(126, 154, 94)
Prasiolite · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Prasiolite, faceted, sparkle
RGB(224, 236, 210)
Carnelian
Chalcedony colored by iron oxides
An orange chalcedony: hydrous iron oxides give its color.
According to CIBJO, it is commonly dyed.
Carnelian · hue
The main hue, the color the gem is named by.
Material: Carnelian, faceted, hue
RGB(200, 88, 42)
Carnelian · light
The light part, where the stone is thinnest or light passes straight through.
Material: Carnelian, faceted, light
RGB(224, 130, 80)
Carnelian · deep
The deepest part, in the facets in shadow.
Material: Carnelian, faceted, deep
RGB(143, 52, 18)
Carnelian · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Carnelian, faceted, sparkle
RGB(240, 168, 120)
Chrysoprase
Chalcedony colored by nickel
A green chalcedony: its color comes from nickel-bearing clays inside the stone.
According to CIBJO, it is never treated.
Chrysoprase · hue
The main hue, the color the gem is named by.
Material: Chrysoprase, faceted, hue
RGB(93, 184, 120)
Chrysoprase · light
The light part, where the stone is thinnest or light passes straight through.
Material: Chrysoprase, faceted, light
RGB(143, 211, 162)
Chrysoprase · deep
The deepest part, in the facets in shadow.
Material: Chrysoprase, faceted, deep
RGB(47, 138, 80)
Chrysoprase · sparkle
The sparkle, where light bounces off the facets back to the eye.
Material: Chrysoprase, faceted, sparkle
RGB(191, 232, 202)
Pigmentoria is an independent color atlas. Gem, variety, place and trade names (for example «pigeon's blood» or «Paraíba») are used descriptively only and do not indicate the origin, quality, treatment or certification of any stone. The colors are our own digital approximations, not official standards of any laboratory. GIA, CIBJO, LMHC, SSEF, Gübelin and the other organisations cited belong to their owners; Pigmentoria is not affiliated with or endorsed by them.