Triphylite (Tryphylite) Value, Price, and Jewelry Information

view gemstone encyclopedia

Medium dark, very slightly greenish brown, triangular step-cut 2.41-ct triphylite, 11.4 x 7.1 mm, Minas Gerais, Brazil. © The Gem Trader. Used with permission.

Triphylite is one of the world’s rarest gems. The IGS had the extraordinary privilege of examining a discovery of facetable material from Brazil that showed previously unknown characteristics.

Triphylite (Tryphylite) Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Triphylite values vary considerably, due to rarity and demand. Some have sold for $250 per carat. At auction, demand has driven prices as high as $4,500 per carat.

Triphylite (Tryphylite) Information

Data Value
Name Triphylite (Tryphylite)
Colors Greenish gray, bluish gray; alters to brownish or blackish hues. (Lithiophilite is clove brown, yellowish brown, honey yellow, or salmon).
Formula Li(Fe+2, Mn+2)PO4 + Mg.  Series to lithiophilite.
Etymology From the Greek words tri and phylon, meaning “family of three,” probably alluding to the presence of three cations (positively charged atoms) in its formula: lithium, iron, and manganese.
Occurrence As a primary mineral in granitic pegmatites, often altered to a wide array of secondary phosphates.
Inclusions Needles, crystals, fingerprints.
Fracture Subconchoidal to uneven
Hardness 4-5
Cleavage Perfect 1 direction
Crystallography Orthorhombic; crystals prismatic, often with rounded faces, but very rare: usually massive, cleavable, and compact.
Refractive Index 1.689-1.702
Birefringence 0.006-0.008
Luminescence None reported.
Luminescence Present No
Absorption Spectrum Some Brazilian material may show a strong line at 485 and a strong to weak line at 460.
Pleochroism Absent or very weak; some lithiophilite may show deep pink/pale greenish yellow/pale pink. See “New Facetable Triphylites from Brazil” below.
Optics a = 1.689-1.694; β = 1.689-1.695; γ = 1.695-1.702. Biaxial (+). See “Identifying Characteristics” below.
Optic Sign Biaxial +
Luster Vitreous; resinous to sub resinous.
Specific Gravity 3.42. Pure Fe end of triphylite-lithiophilite series, 3.58. Pure Mn end, 3.34. (See "Identifying Characteristics" below).
Transparency Transparent to translucent.
Phenomena Some Brazilian gems show slight color change.
triphylite - George Smith Mine, NH

Triphylite, 2.1 x 1.6 x 1.3 cm, George Smith Mine, Claremont, New Hampshire, USA. © Rob Lavinsky, Used with permission.


As any long-term student of gemology knows, the reported properties of gems expand over time. Textbooks written in the 1950s show a narrower range of properties than those written in the 1990s and 2000s. The simple reason is that gemologists have examined more gems. Thus, more information becomes available.

With gems as rare as triphylite (sometimes spelled tryphylite or triphyllite), gemologists have examined very few specimens ever. In addition, this phosphate mineral forms a solid solution series with lithiophilite. As a result, previously unobserved blends can appear. Lithiophilite has a chemical formula nearly identical to triphylite: Li(Mn+2, Fe+2)PO4. It differs by being rich in manganese (Mn) instead of iron (Fe). Due to this lower iron content, lithiophilite is slightly less dense. Its colors run from pinkish to greenish brown, while triphylite’s color is usually a gray shade of blue or green.

lithiophilite - Maine

Lithiophilite, 5.4 x 3.7 x 2.0 cm, Emmons Quarry, Greenwood, Oxford County, Maine, USA. © Rob Lavinsky, Used with permission.

Triphylite is a primary phosphate mineral. It alters easily into other phosphate minerals, especially manganese phosphates. Secondary phosphate minerals include: dickinsonite, eosphorite, fairfieldite,  fillowite, heterosite, hureaulite, phosphoferrite, purpurite, reddingite, salmonsite, sicklerite, stewartite, strengite, triploidite, vivianite, and wolfeite.

New Facetable Triphylites from Brazil

triphylite - faceted stones

Two faceted Brazilian triphylites examined by the IGS.

The new discovery clearly shows the blend, being clove brown and grayish green. Previously studied examples of this gem were just melee size and had very little pleochroism. The newly discovered gems go up to two carats and show beautiful orangish/brown and green pleochroism, similar to andalusite.

Below is a summary of their properties.

  • Refractive Index: 1.680 – 1.695
  • Birefringence: 0.011 – 0.015
  • Color: Clove brown and grayish green.
  • Cleavage: Perfect one direction (basal) and imperfect in two directions (prismatic). All cleavages are at right angles to each other.
  • Absorption Spectrum: Strong line at 485 and strong to weak line at 460.
  • Pleochroism: Orangish/brown and green.

Additional Brazilian material has also demonstrated color change. Some gems have shown slight color change, from greenish brown in daylight to brownish pink or purple in incandescent light.

This 0.99-ct triangle-cut triphylite gem from Minas Gerais, Brazil shows color change, from a dominant green in daylight to flashes of brownish copper red in incandescent light. © The Gem Trader. Used with permission.

Identifying Characteristics


You may sometimes observe triphylites with optic character biaxial (-). Depending on the Fe: Mn ratio, you may observe uniaxial interference figures. Refractive indices increase with Fe content but may substantially decrease if magnesium (Mg) substitutes for (Fe, Mn).

Specific Gravity

  • Pure Fe end of the triphylite-lithiophilite series = 3.58.
  • The pure Mn end (lithiophilite) = 3.34.
  • The halfway point (Fe: Mn = 1:1) = 3.52. Density isn’t linear with Fe: Mn ratio.


Scientists have explored using this mineral, in both natural and synthetic forms, in lithium batteries. However, no commercial jewelry use for lab-created triphylite is known.


None known.

triphylite - Chandler's Mill Mine, NH

Triphylite, Chandler’s Mill Mine, Newport, Sullivan Co., New Hampshire, USA. © Rob Lavinsky, Used with permission.


Minas Gerais, Brazil has produced facetable material. Other notable gem-quality sources include the following:

  • United States: Pala, California; Maine; Massachusetts; New Hampshire (excellent crystals at Chandler’s Mill, Palermo, Grafton Center, North Groton); Black Hills, South Dakota (as enormous crystals up to 6 feet long).
  • Finland; France; Germany; Sweden.

Stone Sizes

Triphylites don’t usually form in distinct crystals. Most crystals appear as compact masses, embedded in other stones, or as inter-grown crystal clumps. Facetable material is very rare. Most gem-quality material is best suited for cabbing.

Conceivably, lapidaries could cut large stones from some of the immense crystals found in South Dakota. However, this material is usually opaque or altered. The Brazilian material has yielded tiny, brown, cut stones.

Triphylites could have more surprises in store for gem collectors. New sources could yield cuttable crystals at any time.


With perfect cleavage and mid-range hardness (4-5), these gems would require great care as jewelry stones. Make sure they have protective settings and avoid ring use. You’re more likely to encounter these rare gems, if at all, in gem collections than jewelry collections.

Store these gems separately from other harder stones to avoid contact scratches. For cleaning, use a soft brush, mild detergent, and warm water. Consult our Gemstone Jewelry Cleaning Guide for more recommendations.

triphylite - emerald cut, Brazil

Triphylite, 1.68 cts, emerald cut, Brazil. This gem looks greenish gray in one direction and shows hints of brownish orange in another. © Rob Lavinsky, Used with permission. (Images combined to compare colors).

Ready to learn how to identify gems on your own?

Join our mailing list below to download a FREE gem ID checklist tutorial. See what’s inside…

• Discover the 17 practical steps to gemstone identification (even if you’re just getting started with gemology)

• Learn how you can use specific tools to gather data, make observations & arrive at an accurate ID

• Explore a range of gemological tests… not only will you get familiar with the process but also time-saving shortcuts!