Pyrophyllite Value, Price, and Jewelry Information

Pyrophyllite resembles talc in many ways and is indistinguishable by eye from soapstone. Chemical tests are needed to distinguish them. North Carolina material is often used in carvings, as is the material from China known as agalmatolite.

Pyrophyllite Value

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Pyrophyllite Information

Data	Value
Name	Pyrophyllite
Crystallography	Monoclinic. Crystals tabular, often curved and deformed; foliated, radial, granular, compact.
Colors	White, yellow, pale blue, grayish green. brownish green.
Luster	Pearly to dull, greasy.
Fracture	Sectile.
Hardness	1-2.
Specific Gravity	2.65-2.90.
Birefringence	0.050
Cleavage	Perfect 1 direction.
Stone Sizes	Cabochons and carvings are cut from massive material, any practical size.
Luminescence	Weak cream white in LW (China) — variety called agalmatolite.
Spectral	Not diagnostic.
Formula	Al₂Si₄O₁₀(OH)₂.

Optics: a = 1.534—1.556; β= 1.586-1.589; γ= 1.596-1.601.

Biaxial (-), 2V = 53—62°.

Vague shadow edge on refractometer at about 1.6.

Occurrence: In schistose metamorphic rocks; also in hydrothermal veins with micas, quartz.

California; Arizona; Deep River, North Carolina; Pennsylvania; Georgia.

Minus Gerais, Brazil; Mexico; Sweden; Belgium;

Switzerland; Japan; USSR; Korea.

Transvaal, South Africa: so-called koranna stone, which is dark gray and is about 86% pyrophyllite; R.I. ~ 1.58, S.G. 2.72; also called South African Wonderstone.

Comments: Pyrophyllite resembles talc in many ways and is indistinguishable by eye from soapstone. Chemical tests are needed to distinguish them. North Carolina material is often used in carvings, as is the material from China known as agalmatolite.

Name: From the Greek words for fire and leaf because of the sheet-like nature and thermal properties of the mineral. Agalmatolile means figure stone, in allusion to its use in carvings.

by Dr. Joel Arem

Pyrophyllite Value, Price, and Jewelry Information