JASPER

:''This article is about the mineral. For other uses see Jasper (disambiguation)''




'Jasper' is an opaque, impure variety of quartz, usually red, yellow or brown in color. This mineral breaks with a smooth surface, and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and at one time for snuff boxes. When the colors are in stripes or bands, it is called ''striped'' or ''banded'' jasper. Jaspilite is a banded iron formation rock that often has distinctive bands of jasper.

Contents

Etymology and historical/mythical usage

Types of jasper

See also

References

Etymology and historical/mythical usage

The name means "spotted stone", and is derived from Anglo-French ''jaspre'', from Old French ''jaspe'', from Latin ''iaspidem'', the accusative of ''iaspis'', from Greek ''iaspis'', via a Semitic language (cf. Hebrew ''yashepheh'', Akkadian ''yashupu''), ultimately from Persian ''yashp''.
The word ''yashepheh'' in the masoretic text of Exodus 28:20, referring to a stone in the Hoshen, is thus reflected in the Septuagint by the word ''Iaspis'', and usually translated into English as ''Jasper''. Despite the most common form of Jasper being red, scholars think that the ''yashepheh'' here actually refers to a green form of Jasper - which was very rare, and so highly prized; the Greeks used ''Iaspis'' to refer to the green form, while the red form simply fell under the term ''Sard'' - which just means ''red''. Rebbenu Bachya argues that this stone represents the tribe of Benjamin, but there is actually a wide range of views among traditional sources about which tribe the stone refers to.
It is described in the Book of Revelation (21:11) as follows: "It shone with the glory of God, and its brilliance was like that of a very precious jewel, like a jasper, clear as crystal."

Types of jasper

Jasper can appear as an opaque rock of shades of red due to mineral impurities. Patterns can arise from the formation process and from flow patterns in the sediment or volcanic ash that was saturated with silica to form jasper, yielding bands or swirls in the rock.
Jasper may be permeated by dendritic minerals providing the appearance of vegetative growths. The jasper may have been fractured and/or distorted after formation, later rebonding into discontinuous patterns or filling with another material. Heat or environmental factors may have created surface rinds (such as varnish) or interior stresses leading to fracturing.
Egyptian jasper is a brown jasper, appearing as nodules in the Libyan desert and in the Nile valley between the Red Sea and Cairo, Egypt, distinguished by a zonal order of light and dark shades of colors. Egyptian jasper is also known as Egyptian pebble.
Picture jaspers simultaneously exhibit several of these variations (such as banding, flow patterns, dendrites or color variations) resulting in what appear to be scenes or images in a cut section (as in Biggs, Deschutes, Owyhee, Poppy and other named types). Spherical flow patterns produce a distinctive orbicular appearance (porcelain jaspers such as Blue Mountain, Bruneau and Willow Creek). Complex mixes of impurities produce wild color variations (as in McDermitt jasper). Healed fractures produce brecciated jasper (such as Canyon Creek). Examples of this can be seen at Llanddwyn Island.
Jasper is the gemstone of the Rooster from the Chinese Zodiac.

See also

★ List of minerals

★ Carnelian

★ Sard

References

★ R. V. Dietrich, ''Gemrocks''

★ Mindat

★ http://www.gemstone.org/gem-by-gem/english/jasper.html