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Topic: Cryptocrystalline

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	Cryptocrystalline - Wikipedia, the free encyclopedia
		Cryptocrystalline is a rock texture which is so finely crystalline, that is, 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 and flint are cryptocrystalline.
		Volcanic rocks, especially of the acidic type such as felsites and rhyolites, may have a cryptocrystalline groundmass as distinguished from pure obsidian (acidic) or tachylyte (basic), which are natural rock glasses.
	en.wikipedia.org /wiki/Cryptocrystal (117 words)

	Tool stone
		Generally speaking, tools that require a sharp edge are made using cryptocrystalline materials that fracture in an easily-controlled conchoidal manner.
		Cryptocrystalline tool stones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite[?], which are igneous flowstones[?]; and obsidian, a form of natural glass created by igneous processes.
		Whereas cryptocrystalline materials are most useful for killing and processing animals, large-grained materials are usually used for processing plant matter.
	www.ebroadcast.com.au /lookup/encyclopedia/to/Tool_stone.html (161 words)

	Research Issues in San Diego Prehistory - Cryptocrystalline Silica
		Cryptocrystalline silica -- rock composed of extremely fine silica (quartz) crystals -- is known by a variety of different names (generally based on differences in translucence, color, texture, or presumed geological origin) including chert, chalcedony, jasper, agate, flint, and petrified wood.
		Cryptocrystalline silica sources in western San Diego County, based on Pigniolo 1992.
		Future archaeological investigations may be able to identify reliable macroscopic and chemical signatures for cryptocrystalline silica derived from various local sources.
	home.earthlink.net /~researchissues/spatial.crypto.htm (604 words)

	[No title]
		Clinopyroxene 38 38 0.06-0.12 Subhedral, acicular Opaques 2 2 n/a n/a Mesostasis 2 2 n/a n/a Cryptocrystalline Vesicles 0 One plag phenocryst is composed of elongated, interfingering of plag and grounmass.
		Opaques 1 1 n/a n/a Mesostasis 10 12 n/a n/a Cryptocrystalline.
		Cryptocrystalline melt inclusions in plag and ol phenocrysts.
	www.ngdc.noaa.gov /mgg/geology/odp/data/106/648B/hrthin.txt (1653 words)

	Quartz as Gems, part 2: Rockhounding Arkansas
		Cryptocrystalline varieties of quartz that have important lapidary applications include agate, jasper, chalcedony, chrysoprase, carnelian, and bloodstone.
		Cryptocrystalline quartz consists of submicroscopic grains of quartz.
		Bloodstone or Heliotrope (the older name) is a cryptocrystalline variety of quartz characterized by a translucent, dark green matrix of stone called plasma with scattered spots of bright, blood-red jasper.
	rockhoundingar.com /quartz/qtzgems02.html (4582 words)

	Quartz
		Cryptocrystalline quartz is quartz in which the crystals are microscopic in size and thus is always opaque or translucent.
		Chalcedony is a translucent or semitranslucent cryptocrystalline quartz, which may be patterned (agate) or uniform in color (blue, green, pink, fl, white, etc.).
		Tigereye is a yellowish brown cryptocrystalline quartz in which quartz has replaced crocidolite, a fibrous, asbestos-like mineral.
	www.tradeshop.com /gems/quartz.html (989 words)

	Gemstone Logic
		Crystalline quartzes are formed in one distinct crystal and owe their color to a variety of trace elements (also referred to as impurities.) Examples of these transparent, facetable gems include amethyst, smoky topaz and citrine.
		Cryptocrystalline quartzes are dense formations of infinitesimally small crystals and stained during their formation by solutions containing metallic salts.
		Cryptocrystalline quartzes include the ornamental ornamental and rock-like varieties and are classified as either chalcedony or agate.
	www.jandavid.com /body_logicdb_46.html (542 words)

	BASEMENT FORMED AT SUPERFAST SPREADING RATE (HOLES 1256C AND 1256D)
		Groundmass grain size varies throughout the section from glassy in the hyaloclastite and in chilled margins of flows to cryptocrystalline (<0.1 mm) or microcrystalline (0.1-0.2 mm) in the interiors of most of the sheet flows to fine-grained (>0.2 mm) in the interior of the massive ponded flow.
		The groundmass is cryptocrystalline to microcrystalline in flow interiors, decreasing in average grain size toward the margins (Fig.
		The lowermost 1.6-m-thick core of Unit 1256C-18 is an aphyric cryptocrystalline basalt with an unusual groundmass texture of equigranular clinopyroxene and magnetite with sparse plagioclase laths and that reflects recrystallization at near-magmatic temperatures (Fig.
	www-odp.tamu.edu /publications/206_IR/chap_03/c3_5.htm (16301 words)

	Quartz - HorologicalWiki (Site not responding. Last check: 2007-10-13)
		The most important distinction between types of quartz is that of macrocrystalline (individual crystals visible to the unaided eye) and the microcrystalline or cryptocrystalline varieties (aggregates of crystals visible only under high magnification).
		The cryptocrystalline varieties are either translucent or mostly opaque, whilst the transparent varieties tend to be macrocrystalline.
		Colour is a secondary identifier for the cryptocrystalline minerals, whilst colour is a primary identifier for the macrocrystalline varieties.
	www.clockmakers.archivist.info /wiki/wiki.phtml?title=Quartz (458 words)

	Chalcedony (Site not responding. Last check: 2007-10-13)
		As is clear by now, chalcedony is not one mineral but the name given to a whole family of minerals just like quartz, In fact, chalcedony is a kind of cryptocrystalline quartz, however unlike quartz, it is not clear and glassy to look at, rather it is translucent to opaque and has a waxy lustre.
		The atoms in cryptocrystalline quartz pack together to form stones that are either opaque or translucent, The atoms take the form of fibres rather than crystals and there is often water or air trapped between the layers of fibres.
		Actually cryptocrystalline means that there are crystals but thatthey are so microscopically small that they cannot be seen without very high magnification.
	www.design4you.co.th /chalcedony.html (1928 words)

	Crystal Quartz
		Cryptocrystalline quartz consists of individual crystals too small to be easily distinguishable under the microscope.
		The Cryptocrystalline varieties of quartz may be separated into two types.
		Chert is the general term applied to the granular Cryptocrystalline varieties of Quartz.
	www.seabgems.com /crystal_quartz.htm (933 words)

	Crystal (mineral) - MSN Encarta
		For example, argentite, a common silver ore, crystallizes in the same class as garnet and salt, but usually occurs in irregular cryptocrystalline masses.
		Much work has been done in recent years on the preparation of single crystals of substances that are normally cryptocrystalline.
		Large, single crystals of metals, for example, can be grown by a number of methods, the simplest of which is to melt the metal in a conical vessel, and then lower the vessel slowly from the furnace, point first.
	encarta.msn.com /encyclopedia_761570052_3/Crystal_(mineral).html (503 words)

	CHALCEDONY
		The atoms in cryptocrystalline quartz pack together to form stones that are either opaque or translucent.
		The jaspers are often opaque, while the chalcedonies tend to be transparent.
		Because there are too many cryptocrystalline quartzes to describe in one article, we'll use the commonly accepted groupings.
	www.suite101.com /article.cfm/gems_and_minerals/40360 (400 words)

	[No title]
		Mesostasis 68.8 75.2 Cryptocrystalline; some of the groundmass is replaced by a yellowish-brown clay mineral (fibrous to patchy).
		Opaques Tr Tr <=0.005 In mesostasis at margins of cryptocrystalline sheafs.
		Mesostasis 51 68.6 Microcrystalline to cryptocrystalline; varitextured from plumose to comb to sheaf-spherulitic consisting of brown amorphous matter + feathery cpx(?) + opaques.
	www-odp.tamu.edu /publications/168_IR/TS1027.TXT (3516 words)

	Quartz Page
		Cryptocrystalline: masses made up of either fibrous or granular aggregates of quartz.
		Chalcedony: the general term used to describe the fibrous variety of cryptocrystalline quartz.
		Agate: usually a banded material that is translucent and may contain any number of colors or combinations.
	www.theimage.com /gemstone/quartz/quartz.html (669 words)

	[No title]
		Eighty-two cryptocrystalline sites were spatially referenced using Nevada 1:100,000 scale digital raster graphic (DRG) maps in UTM projection as background images (Nevada Bureau of Mines and Geology, 1996).
		The size of the polygon represents the distributed or scattered area of the cryptocrystalline material, not the amount of material.
		The cryptocrystalline materials considered were chalcedony, chert, jasper, opal, obsidian, and cutting materials.
	geopubs.wr.usgs.gov /open-file/of99-523/rkhnd.txt (663 words)

	Case Studies - PTTC Rockies (Site not responding. Last check: 2007-10-13)
		This early dolomitization produced cryptocrystalline dolomite (10 microns).
		Dolomites in the Red River D zone are characterized by sparse cryptocrystalline and abundant fabric destructive, medium-crystalline (60-200 microns), euhedral to subhedral replacement crystals.
		These dolomites produce the best conventional reservoirs within the project area and were formed by late diagenetic replacement or recrystallization of cryptocrystalline dolomites in the deep subsurface.
	www.mines.edu /research/PTTC/casestudies/lecrr/upper5.html (382 words)

	Research Issues in San Diego Prehistory - Toolstone Preferences
		James R. Moriarty III (1966:21, 23) suggested that the use of cobbles from conglomerate lenses was one of the main criteria for defining La Jolla I (ca.
		A Late Prehistoric technological shift to arrowpoints and other small tool types allowed for greater exploitation of toolstones that were available primariy in small nodules, such as quartz, cryptocrystalline silica, and obsidian, although it did not interfere with the continued use of Santiago Peak volcanics in locations where the latter were available.
		Dietler concluded that Late Prehistoric toolstone selection was based on a combination of local availability and material preferences, with obsidian and cryptocrystalline silica being ranked higher than volcanic rock, and volcanic rock ranked above quartz and quartzite.
	home.earthlink.net /~researchissues/resource.toolstone.htm (478 words)

	RedOrbit - Reference Library (Site not responding. Last check: 2007-10-13)
		Chert is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils.
		It outcrops as nodules in limestone, chalk, and dolostone formations as a replacement mineral, as well as in thin beds when it is a primary deposit, and is generally considered to be less attractive and more common than flint, although the two materials are closely related.
		The cryptocrystalline nature of chert, combined with its above average ability to resist weathering, recrystallisation and metamorphism has made it an ideal rock for preservation of early life forms.
	www.redorbit.com /education/reference_library?article_id=452 (518 words)

	Description of Carbonate Rocks
		The foundation of Folk’s classification is the relative amounts of (1) allochems, (2) calcite cement or 'spar", and (3) microcrystalline to cryptocrystalline calcite matrix or 'micrite.
		Similarly any microcrystalline to cryptocrystalline carbonat grain over 2mm in diameter and regardless of its true origins is referred to as an intraclasts.
		In the pure sense of folk's classification all four rocks could exists however in practice since one is forced to attributes all microcrystalline to cryptocrystalline calcite grains under 2 mm in diameter to the pellets or pelloids the terms intrasparite and intramicrite are not used.
	people.uncw.edu /dockal/gly312/carbonate/carbonate.htm (2193 words)

	Golden Gate Photo - Glossary of Technical Terms
		A variety of quartz composed of cryptocrystalline (too small to be seen through an ordinary microscope) silica.
		The Cenozoic Era is subdivided into the Tertiary and Quaternary periods (on a different basis, it is subdivided into the Paleogene and Neogene periods).
		Hard, dense, and chiefly composed of microcrystalline (crystals that can only be seen through a microscope) or cryptocrystalline (crystals too small to be seen with a microscope) quartz.
	www.goldengatephoto.com /glossary.html (2210 words)

	Magnesia - Forms, Applications and Production Processes
		Cryptocrystalline magnesite is generally of a higher purity than macrocrystalline ore, but tends to occur in smaller deposits than the macrocrystalline form.
		QMAG is a producer of refractory grade fused magnesia.
		Historically, and due principally to the small size of most known cryptocrystalline deposits, production of high grade magnesia products was mainly by extraction from natural brines or seawater (synthetic MgO), a high cost and energy intensive process.
	www.azom.com /details.asp?ArticleID=1343 (1597 words)

	Six Groups of Pedofeatures are Distinguished
		Smaller crystal are considered to be part of the groundmass or as cryptocrystalline pedofeatures.
		Amorphous and Cryptocrystalline Pedofeatures are isotropic between crossed polarizers, except for inclusions of birefringent organic and/or mineral basic components.
		The most common mineral amorphous or cryptocrystalline pedofeatures are segregations of iron and manganese oxides/hydroxides associated with poor drainage and anaerobic conditions.
	www.ces.ncsu.edu /plymouth/programs/six.html (733 words)

	Delaware Department of Transportation - Projects
		Quartz displayed a similar distribution to quartzite at the small end of the scale, indicating considerably fewer small flakes in comparison to both pebble chert and Iron Hill jasper.
		Notably, the remainder of the quartz graph paralleled the cryptocrystalline materials.
		The low incidence of small quartz flakes suggested little thinning or finishing of quartz, and implied that knapping was more often aimed at the production of larger flakes, suitable for use as tools, rather than the reduction of a core into a bifacial tool.
	www.deldot.net /static/projects/archaeology/lums_pond/lums36.shtml (691 words)

	Gemology Lesson 2
		Some minerals form in clusters of microscopic crystals; these gemstones are called "cryptocrystalline".
		Cryptocrystalline materials will usually be translucent to opaque rather than transparent.
		Chalcedony is a cryptocrystalline form of quartz; varieties of chalcedony include agates, chrysoprase, and bloodstone.
	www.fortunecity.com /meltingpot/cranley/1170/crystallography.htm (655 words)

	Flint vs. Chert....whats the difference? (Site not responding. Last check: 2007-10-13)
		(silicon dioxide) and is most abundantly represented in nature by pure quartz and its many cryptocrystalline forms.
		Cryptocrystalline quartz is simply quartz whose crystals are so small that they can only be seen with the aid of a high-power microscope.
		Chalcedony is a variety of cryptocrystalline quartz with extremely small crystals and a specific gravity (weight under water, a measure of a rock/mineral's purity) nearly identical to that of pure quartz.
	www.theaaca.com /Learning_Center/flintvs.htm (509 words)

	QUARTZ (Silicon Dioxide)
		Cryptocrystalline (crystals too small to be seen even by a microscope) varieties are also used as semi-precious stones and for ornamental purposes.
		Luster is glassy to vitreous as crystals, while cryptocrystalline forms are usually waxy to dull but can be vitreous.
		Crystal Habits are again widely variable but the most common habit is hexagonal prisms terminated with a six sided pyramid (actually two rhombohedrons).
	www.galleries.com /minerals/silicate/quartz/quartz.htm (1104 words)

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