Howlite Value, Price, and Jewelry Information


HOWLITE: California (nodule ~ 3 inches across). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Howlite is always opaque in nodules; it is an abundant material and easy to acquire. Sometimes it contains black, threadlike impurities resembling the veining in turquoise. Howlite is frequently dyed blue to resemble turquoise, and it makes a most convincing simulant. The white material is relatively unexciting in appearance.

Howlite Value

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

Howlite Information

DataValue
NameHowlite
Crystallography Monoclinic. Crystals tiny; usually nodular masses, chalky or porcellaneous.
Colors White, opaque except in tiny grains.
Luster Subvitreous.
Hardness 3.5 or less.
Specific Gravity 2.45-2.58.
Birefringence 0.022
Cleavage Smooth and even fracture.
Stone SizesSpheres up to about 8 inches in diameter have been cut; also seen as cabochons and tumble-polished stones.
Luminescence Brownish yellow in SW; some California material deep orange in LW.
Spectral Not diagnostic.
FormulaCa2B5SiO9(OH)5
Pleochroism None

Optics:  a = 1.583-1.586;  β= 1.596-1.598;  γ= 1.605.

Biaxial (-), 2V large.

Occurrence: Microscopic crystals or nodules occur in arid regions or borate deposits.

California: abundant nodules, up to a weight of several hundred pounds, as at Lang in Los Angeles County Also occurs in the Mohave Desert, California. Nova Scotia: small nodules.

Comments: Howlite is always opaque in nodules; it is an abundant material and easy to acquire. Sometimes it contains black, threadlike impurities resembling the veining in turquoise. Howlite is frequently dyed blue to resemble turquoise, and it makes a most convincing simulant. The white material is relatively unexciting in appearance.

Name: After H. How who described a mineral of approximately the same composition.