Jasper, an aggregate of microgranular

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

and/or

cryptocrystalline Cryptocrystalline is a rock microstructure, rock texture made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert a ...

chalcedony and other mineral phases, is an opaque, impure variety of

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III) inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as a

gemstone A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewellery, jewelry or other adornments. Certain Rock (geology), rocks (such ...

. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

of jasper is typically 2.5 to 2.9 g/cm³. Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.

Etymology and history

Egyptian - Finger Ring with a Representation of Ptah - Walters 42387 - Side A

The name means "spotted or speckled stone," and is derived via

Old French Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th Anglo-Norman ''jaspe'') and Anglo-Norman language">Anglo-Norman ''jaspe'') and

Greek ''iaspis'' (feminine noun), from an Afroasiatic languages">Afroasiatic language (cf. Hebrew language">Hebrew Hebrew (; ''ʿÎbrit'') is a Northwest Semitic languages, Northwest Semitic language within the Afroasiatic languages, Afroasiatic language family. A regional dialect of the Canaanite languages, it was natively spoken by the Israelites and ...

' , Akkadian ''yashupu''). This Semitic etymology is believed to be unrelated to that of the English given name Jasper, which is of Persian language">Persian origin, though the Persian word for the mineral jasper is also ''yashum'' ( یَشم). Green jasper was used to make bow drill">:fa:یشم">یَشم). Green jasper was used to make

bow_drill.html" ;"title=":fa:یشم">یَشم). Green jasper was used to make bow drill">:fa:یشم">یَشم). Green jasper was used to make bow drills in Mehrgarh between 4th and Jasper is known to have been a favorite gem in the ancient world; its name can be traced back in Arabic language">Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

, Persian, Hebrew, Assyrian, Greek and Latin. On Minoan civilization, Minoan Crete, jasper was carved to produce seals circa 1800 BC, as evidenced by archaeological recoveries at the palace of Knossos. Although the term jasper is now restricted to opaque quartz, the ancient ''iaspis'' was a stone of considerable translucency including nephrite. The jasper of antiquity was in many cases distinctly green, for it is often compared to

emerald Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr., and Kammerling, Robert C. (1991). ''Gemology'', John Wiley & Sons, New York ...

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. 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. Harappa red jasper male torso

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 Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

Hydrothermal circulation Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

is generally thought to be required in the formation of jasper. 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. 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 formation Banded iron formations (BIFs; also called banded ironstone formations) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness and e ...

s (BIFs) which indicate low, but present, amounts of dissolved oxygen in the water such as during the

Great Oxidation Event The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere an ...

or snowball earths. 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 Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

, especially in Purbalingga district. From the US,

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

's Biggs jasper and

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

's Bruneau jasper from the Bruneau River canyon are particularly fine examples. Other examples can be seen at Ynys Llanddwyn in

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. 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 Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

, is noted for its colossal, open-cast

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

mine.)

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 Theophrastus (; ; c. 371 – c. 287 BC) was an ancient Greek Philosophy, philosopher and Natural history, naturalist. A native of Eresos in Lesbos, he was Aristotle's close colleague and successor as head of the Lyceum (classical), Lyceum, the ...
in his book ''On Stones'' (
Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
title: : ''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 Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
.

Basanite (not to be confused with bassanite), ''Lydian stone'', and

radiolarite Radiolarite is a Siliceous ooze, siliceous, comparatively hard, fine-grained, chert-like, and homogeneous sedimentary rock that is composed predominantly of the microscopic remains of radiolarians. This term is also used for Friability, indurat ...

(a.k.a. lydite or flinty slate) are terms used to refer to several types of black, jasper-like rock (also including tuffs,

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

s and siltstones) 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 Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically re ...

is named for the ancient kingdom of

Lydia Lydia (; ) was an Iron Age Monarchy, kingdom situated in western Anatolia, in modern-day Turkey. Later, it became an important province of the Achaemenid Empire and then the Roman Empire. Its capital was Sardis. At some point before 800 BC, ...

in what is now western

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

. A similar rock type occurs in

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

. Such rock types have long been used for the making of touchstones to test the purity of

precious metal Precious metals are rare, naturally occurring metallic chemical elements of high Value (economics), economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less reactivity (chemistry), chemically reac ...

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

s, 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 Petrology () is the branch of geology that studies rocks, their mineralogy, composition, texture, structure and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous ...

- and

mineralogy Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...

-related field of study.

Gallery

File:Jasper (32132824820).jpg, Red jasper rough, Cave Creek, Arizona File:Jasper-poloski.jpg, Dull red jasper veined with white quartz, rough, provenance: uncertain – possibly Crimea or

Kyrgyzstan Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...

File:jasper.pebble.600pix.bkg.jpg , Brecciated red jasper tumbled smooth, File:Cherry Creek Jasper (China) (40126258670).jpg, Red-green-and-yellow jasper cabochon, Cherry Creek, China file:Jasper-brek4iya.jpg, Brecciated yellow-and-green jasper, cut and polished, Kara Dag,

Crimea Crimea ( ) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukrain ...

File:Cut and oiled yellow jasper 3.JPG , Brecciated yellow jasper, cut and oiled File:Saint-Jacut-les-Pins - Tropical Parc, musée des minéraux (14).jpg, Green-yellow-and-orange polished jasper boulder, Tropical Parc, musée des mineraux, Saint-Jacut-les-Pins,

Brittany Brittany ( ) is a peninsula, historical country and cultural area in the north-west of modern France, covering the western part of what was known as Armorica in Roman Gaul. It became an Kingdom of Brittany, independent kingdom and then a Duch ...

File:Green and Red Jasper IMG 9478.jpg, Green-and-red jasper pebble with areas of grey, translucent chalcedony,

Aomori Prefecture is a Prefectures of Japan, prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori (city), Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is border ...

, Shichiri Nagahama, Japan File:Tabu Tabu Jasper (South Africa) (41889473312).jpg, Cabochon of Tabu Tabu jasper (brecciated, with angular clasts cemented by grey chalcedony)

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

File:Bloodstone 3 (49036281801).jpg, Jasper variety bloodstone, provenance doubtful, possibly Deccan Traps India File:Jaspi verd, montjuic, barcelona.jpg , Multi-coloured, banded jasper rough, Montjuïc,

Barcelona Barcelona ( ; ; ) is a city on the northeastern coast of Spain. It is the capital and largest city of the autonomous community of Catalonia, as well as the second-most populous municipality of Spain. With a population of 1.6 million within c ...

File:Kaleidoscope Jasper from Oregon.jpg , Kaleidoscope jasper rough,

File:Poppyjasper.jpg, Poppy jasper (an orbicular jasper from Morgan Hill,

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

), rough File:Poppyjasperpolished.JPG, Poppy jasper: small, polished slabs, Morgan Hill, California File:Freiberg, Terra mineralia, Augenjaspis.JPG, Orbicular "ocean jasper" (not, strictly, a jasper, but a highly silicified

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

or tuff) Analalava District

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

, polished slab File:Jaspe orbiculaire Madagascar 1597B.jpg , Orbicular "ocean jasper", , Analalava District, Madagascar File:Bruneau Jasper from Idaho Thundereggs.jpg , Bruneau jasper,

(this jasper occurs within thundereggs), A. E. Seaman Mineral Museum File:Mookaite (Windalia Radiolarite Formation, Lower Cretaceous; Western Australia).jpg, "Mookaite" (a radiolarian chert from the Windalia Radiolarite Formation,

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

), rough File:Biggs jasper on carpet.jpg, Biggs jasper,

File:Jasper Dalmatian (212237453).jpeg, " Dalmatian jasper" – not a jasper at all but a form of the igneous rock perthite. The black spots are composed of the rare

amphibole Amphibole ( ) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...

arfvedsonite (and not, as often claimed, of tourmaline). Polished pebble. File:Black and white striped

Zebra Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: Grévy's zebra (''Equus grevyi''), the plains zebra (''E. quagga''), and the mountain zebra (''E. ...

Etymology and history

Types

Banded iron formations

Picture jaspers

Basanite and other types of touchstone

Gallery

Footnotes

References

External links