Jasper

Amygdaloid seal
MFA# 1971.163

Description

An opaque, dense cryptocrystalline Quartz stone. Jasper is associated with iron ores and contains irons impurities which give it a yellow, red, brown and occasionally green or blue color. The colors may be uniform, blotchy, or arranged in bands. When the colors are arrange in bands, the mineral is called riband jasper. A variety containing red and green alternating bands is called Siberian jasper. Jasper has been gathered or mined since Paleolithic times. Red, yellow and green jasper was used by the Egyptians for carved cylinder seals and amulets. Egyptian jasper is a variety that is red with brown areas. It was primarily used in the Middle Kingdom period. Currently, jasper is cut and polished as a ornamental building stone. Black jasper and black slate have long been used as touchstones to determine the presence of gold in gold-silver alloys.

Cylinder seal
MFA# 28.855

Synonyms and Related Terms

riband jasper; Siberian jasper; chalcedony; Jaspis (Deut.); jaspe (Esp., Fr., Port.); isapidem (Lat.); iaspis (Gr.); yashp (Persian); jaspis (Ned.)

Raman

Raman

Physical and Chemical Properties

• No visible crystals
• Fracture = conchoidal, uneven, splintery
• Luster = waxy to vitreous
• Streak = white
• Fluorescence = generally inert
• Pleochroism = absent

Composition	SiO2
Mohs Hardness	6.5-7.0
Density	2.59-2.61 g/ml
Refractive index	1.535 - 1.539
Birefringence	undetectable to 0.04 Comparisons Properties of Common Gemstones Additional Images Red jasper pebble Jasper Jasper Resources and Citations Mineralogy Database: Quartz Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing) Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982 A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962 Encyclopedia Britannica, http://www.britannica.com Comment: "jasper" [Accessed November 6, 2001]. C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979 Wikipedia: http://en.wikipedia.org/wiki/Jasper (Accessed Sept. 7, 2005) Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976 Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997 The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998