Phenakite Value, Price, and Jewelry Information

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Phenakite, 12.69 cts, Takowaja River Area, Ural Mountains, Russia. © Rob Lavinsky, www.iRocks.com. Used with permission.

Rare phenakite is a very hard gem material suitable for jewelry. Usually colorless, cut stones have little fire but can be very bright.

Phenakite Value

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Phenakite Information

Data Value
Name Phenakite
Crystallography Hexagonal (trigonal). Crystals rhombohedral, prismatic, acicular; also granular, and in fibrous spherulites.
Crystallographic Forms
Refractive Index 1.654-1.760
Colors Colorless; also yellow. pink, brown, pinkish red, all due to surface stains; some crystals are colored by impurities.
Luster Vitreous
Hardness 7.5-8
Fracture Conchodial
Specific Gravity 2.93-3.00
Birefringence 0.016
Cleavage Indistinct, 1 direction.
Dispersion 0.005
Luminescence Pale greenish or blue in UV light, occasionally pale rose. Sometimes fluoresces blue in X-rays.
Luminescence Present Yes
Luminescence Type Fluorescent, X-ray Colors
Enhancements Radiation
Typical Treatments Irradiation
Transparency Transparent
Absorption Spectrum Not diagnostic
Phenomena Chatoyancy
Formula Be2SiO4.
Pleochroism Observed in strongly colored crystals; for example, in a greenish-blue stone: violet-red/intense blue.
Optics o = 1.654; e = 1.670. Uniaxial (+).
Optic Sign Uniaxial +
Etymology From the Greek phenakos for “deceiver,” because this gem was mistaken for quartz.
Occurrence In granite pegmatites, often in good crystals. Also, schist-hosted deposits of emerald and alexandrite.
Inclusions Crystals of aikinite; also mica (Brazil). Fine, needle-like tubes can cause cat's eye stones in rare cases.
phenakites - rough and cut - Colorado

Phenakites: Colorado (stone ~2.5). Photo © Joel E. Arem, PhD, FGA. Used with permission.

What is Phenakite?

Phenakite lends its name to the phenakite mineral group. The gemstone known as phenakite itself is the beryllium analogue of this group. The gem willemite is the zinc analogue. (Although a very rare element, beryllium also occurs in well-known gemstones such as emeralds and alexandrites).

Does Phenakite Make a Good Jewelry Stone?

Phenakites can show pale yellow, pink, and brown colors, as well as no color. (You’ll seldom see very rare red gems cut from Russian material). With little dispersion, these gems hadn’t generated much excitement beyond collectors of unusual minerals. However, the surge of New Age interest in crystals in the 1990s caught up with this stone. With or without mystical auras, exceptional hardness (7.5 to 8) and indistinct cleavage make this a good, if unusual, stone for any type of jewelry.

Recently, gemological laboratories have confirmed cat’s eye gems cabbed from phenakites from Madagascar and Sri Lanka. The potential for this striking visual effect has contributed to phenakite’s new appeal.

phenakites - rough and finished - Nigeria

This phenakite rough, 127 cts, from Nigeria (top) yielded this beautiful finished gem, 35.95 cts, 21 mm. © Dan Stair Custom Gemstones. Used with permission.

Are Phenakites Safe to Wear?

As finished gemstones, phenakites pose no health hazards. Concerns have been raised over the safety of these gems since they contain beryllium. However, this element is stable within phenakite and isn’t bio-reactive.

On the other hand, faceters should take precautions against inhaling and accidentally ingesting particles when working with phenakite. Of course, faceters should take these same precautions when cutting any gem material.

The Mindat forum contains an informative thread regarding phenakites and purported health risks.

Are There Synthetic Phenakites?

Labs have synthesized this mineral, starting with a seed of willemite, no less. However, there’s no known jewelry use for this material.

When found in emeralds as inclusions, phenakites themselves commonly indicate synthetic origins.

Radiation treatments can turn colorless phenakites yellow-brown.

Distinguishing Phenakite from Quartz and Diamond

Whether rough or finished, this mineral can live up to its etymology as a “deceiver.” You might encounter quartz gems erroneously or deliberately presented as phenakites, since they can resemble each other. However, phenakites have higher refractive indices, birefringence, and specific gravity values than quartzes.

In at least one case, near-colorless phenakite rough was submitted for gemological analysis as suspected diamond. Despite outward similarities, including trigon-like features, these gems have very different optical and physical properties. For example, phenakite has lower dispersion, hardness, and specific gravity than diamond. Diamond also has no birefringence.

phenakite crystal - Brazil

“If you didn’t know it was a phenakite,” quips Rob Lavinsky, “you would swear it was a killer Herkimer Diamond.” Indeed, this observation points to two possible misidentifications for these gems. People have confused phenakites, like this beautiful Brazilian specimen, with both quartz and diamond gems. (So-called “Herkimer Diamonds” are actually double-terminated, water-clear quartz stones). © Rob Lavinsky, www.iRocks.com. Used with permission.

Where are Phenakites Found?

Gem-quality sources include the following:

  • United States: Pala County, California; Colorado (Pike’s Peak area); Lords Hill, Maine; New Hampshire; Virginia (crystals up to 2 inches across).
  • Habachtal, Austria: small gemmy colorless or yellowish crystals.
  • San Miguel de Paracicaba, Brazil: large colorless crystals, often clean and cuttable.
  • Russia: reddish color gems.
  • Czech Republic; France; Madagascar; Myanmar; Klein Spitzkopje, Namibia; Nigeria; Kragero, Norway; Slovakia; Sri Lanka; Switzerland; Usugara district, Tanzania.

Stone Sizes

Faceted gemstones normally range between 1 and 5 carats in size.

Crystals up to 5 x 10 x 18 cm have been found, although usually heavily flawed. The largest known rough was a pebble found in Sri Lanka. Weighing in at 1,470 carats, it cut a 569 carat clean gem and several smaller stones. The large stone has many needle-like inclusions.

  • Smithsonian Institution (Washington, DC): 22.2 (colorless, Russia); 21.9 (colorless, Brazil).
  • National Museums of Canada (Ottawa, Ontario): 23.41 (colorless, Brazil).
  • Private Collection: 21.21, 19.17 (colorless, Russia).

Caring for Phenakites

These gems require no special care. See our Gemstone Jewelry Cleaning Guide for care recommendations.

This video shows the finished 35.95-ct Nigerian phenakite in full view. Video © Dan Stair Custom Gemstones. Used with permission.

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