The name means "spotted or speckled stone," and is derived via
Old Frenchjaspre (variant of
Anglo-Normanjaspe) and
Latiniaspidem (nom. iaspis) from
Greekἴασπιςiaspis (feminine noun),[6] from an
Afroasiatic language (cf.
Hebrewישפהyashpeh,
Akkadianyashupu).[7] This Semitic etymology is believed to be unrelated to that of the English given name
Jasper, which is of
Persian origin,[8][a] though the Persian word for the mineral jasper is also yashp (
یَشم).
Green jasper was used to make
bow drills in
Mehrgarh between 4th and 5th millennium BC.[9] Jasper is known to have been a favorite gem in the ancient world; its name can be traced back in
Arabic, Persian, Hebrew, Assyrian, Greek and
Latin.[10] On
MinoanCrete, jasper was carved to produce seals circa 1800 BC, as evidenced by archaeological recoveries at the palace of
Knossos.[11]
Although the term jasper is now restricted to opaque quartz, the ancient iaspis was a stone of considerable translucency including
nephrite.[2] The jasper of antiquity was in many cases distinctly green, for it is often compared to
emerald and other green objects. Jasper is referred to in the Nibelungenlied as being clear and green. The jasper of the ancients probably included stones which would now be classed as
chalcedony, and the emerald-like jasper may have been akin to the modern
chrysoprase. The Hebrew word may have designated a green jasper.[12]Flinders Petrie suggested that the odem – the first stone on the
High Priest's breastplate – was a red jasper, whilst tarshish, the tenth stone, may have been a yellow jasper.[13]
Types
Jasper is an
opaque rock of virtually any colour stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica-rich
sediment or
volcanic ash.
Hydrothermal circulation is generally thought to be required in the formation of jasper.[14]
Jasper can be modified by the diffusion of minerals along discontinuities providing the appearance of vegetative growth, i.e.,
dendritic. The original materials are often fractured and/or distorted, after deposition, into diverse patterns, which are later filled in with other colorful minerals. Weathering, with time, will create intensely colored superficial rinds.
The classification and naming of jasper varieties presents a challenge.[15] Terms attributed to various well-defined materials includes the geographic locality where it is found, sometimes quite restricted such as "Bruneau" (a canyon) and "Lahontan" (a lake), rivers and even individual mountains; many are fanciful, such as "forest fire" or "rainbow", while others are descriptive, such as "autumn" or "porcelain". A few are designated by the place of origin such as a brown Egyptian or red African.
Banded iron formations
Jasper is the main component in the silica-rich parts of
banded iron formations (BIFs) which indicate low, but present, amounts of dissolved oxygen in the water such as during the
Great Oxidation Event or snowball earths.[16] The red bands are microcrystalline red chert, also called jasper.
Picture jaspers
Picture jaspers exhibit combinations of patterns resulting in what appear to be scenes or images, when seen on a cut section. Such patterns include banding from flow or depositional patterns (from water or wind), as well as dendritic or color variations. Diffusion from a center produces a distinctive
orbicular appearance, i.e., leopard skin jasper or linear banding from a fracture as seen in
liesegang jasper. Healed, fragmented rock produces
brecciated (broken) jasper.
While these "picture jaspers" can be found all over the world, specific colors or patterns are unique to the geographic region from which they originate. One source of the stone is
Indonesia, especially in
Purbalingga district. From the US,
Oregon's
Biggs jasper and
Idaho's
Bruneau jasper from the
Bruneau River canyon are particularly fine examples. Other examples can be seen at
Ynys Llanddwyn in
Wales.[17] A blue-green jasper occurs in a deposit at Ettutkan Mountain,
Staryi Sibay,
Bashkortostan, Russia. (The town of Sibay, in the far south of the
Ural Mountains, near the border with
Kazakhstan, is noted for its colossal, open-cast
copper mine.)[18]
Basanite and other types of touchstone
Basanite is a deep velvety-black variety of amorphous quartz, of a slightly tougher and finer grain than jasper, and less splintery than hornstone. It was the Lydian stone or touchstone of the ancients. It is mentioned and its use described in the writings of
Bacchylides about 450 BC, and was also described by
Theophrastus in his book On Stones (
Ancient Greek title: Περὶ λίθων: Peri Lithon), a century later. It is evident that the touchstone that
Pliny had in mind when he wrote about it was merely a dense variety of
basalt.[19]
Basanite (not to be confused with
bassanite), Lydian stone, and
radiolarite (a.k.a. lydite or flinty slate) are terms used to refer to several types of black, jasper-like rock (also including
tuffs,
cherts and
siltstones)[20] which are dense, fine-grained and flinty / cherty in texture and found in a number of localities. The "Lydian Stone" known to the
Ancient Greeks is named for the ancient kingdom of
Lydia in what is now western
Turkey. A similar rock type occurs in
New England. Such rock types have long been used for the making of
touchstones to test the purity of
precious metalalloys, because they are hard enough to scratch such metals, which, if drawn (scraped) across them, show to advantage their metallic
streaks of various (diagnostic) colours, against the dark background. There are, confusingly, not one but two rocks called basanite, one being a black form of jasper and the
other a black volcanic rock closely akin to basalt. Add to this the fact that many different rock types – having in common the colour black and a fine texture – have, over the ages, been pressed into service as touchstones and it will be seen that there is ample scope for confusion in this
petrology- and
mineralogy-related field of study.[21]
"
Dalmatian jasper" – not a jasper at all but a form of the igneous rock
perthite. The black spots are composed of the rare
amphibolearfvedsonite (and not, as often claimed, of tourmaline). Polished pebble.
Footnotes
^
"Jasper: The usual English form of the name assigned in Christian folklore to one of
the three magi or 'wise men', who brought gifts to the infant Christ at his birth (Matthew 2:1). The name [Jasper] does not appear in the Bible, and is first found in medieval tradition. It seems to be ultimately of Persian origin, from a word meaning 'treasurer'. There is probably no connection with the English vocabulary word jasper denoting a gemstone, which is of Semitic origin." — Hanks, Hardcastle, & Hodges (2006)[8]
^Dietrich, R.V. (23 May 2005).
"Jasper". cst.cmich.edu. GemRocks. Central Michigan University. Archived from
the original on 9 March 2012. Retrieved 16 October 2006.
^
abOne or more of the preceding sentences incorporates text from a publication now in the
public domain: Rudler, Frederick William (1911). "
Jasper". In
Chisholm, Hugh (ed.). Encyclopædia Britannica (11th ed.). Cambridge University Press.
^Hastings's Dict. Bible. 1902, cited in Encyclopædia Britannica (1911).[12].
^"Jasper". Prehistoric Online. Retrieved 10 June 2022.
^Dake, H.C.; Fleener, Frank L.; Wilson, Ben Hur (1938). Quartz Family Minerals: A handbook for the mineral collector. Whittlesey House (McGraw Hill).
^Moore, D.T.; Oddy, W.A. (1 January 1985). "Touchstones: Some aspects of their nomenclature, petrography and provenance". Journal of Archaeological Science. 12 (1): 59–80.
Bibcode:
1985JArSc..12...59M.
doi:
10.1016/0305-4403(85)90015-9.
^"Basanite". Mindat.org. 15 October 2012. Retrieved 24 March 2013.