noun
definition
The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO2. It occurs in a variety of forms, both crystalline and amorphous. Found in every environment.
Examples of quartz in a Sentence
The rocks are probably of quartz, i.e.
Gold is obtained chiefly from quartz reefs, but there are still some important alluvial deposits being worked.
Gold occurs in quartz veins traversing various formations (some as young as Jurassic), and also in gravels, which were for the most part deposited previous to the uplift of the Sierra block.
The gangue was quartz, very irregularly distributed in bodies often of great sizes, for the most part nearly or quite barren of ore.
Chalcedony may be regarded as a micro-crystalline form of quartz.
I am going to attempt this, for the first time ever, with a 500 watt quartz halogen bulb!
When looking for a watch for a nurse, fashionable quartz watches could be just the thing.
There are gold-bearing quartz reefs at Madibi, near Mafeking, where mining began in 1906.
This mature weathering, resulting in the relatively complete separation of the quartz from the kaolin, and both from the calcium carbonate and other basic materials, implies conditions of rock decay comparable to those of the present time.
A series of quartzites and slates referred to the Cambrian, and holding numerous and important veins of auriferous quartz, characterize its Atlantic or southeastern side, while valuable coal-fields occur in Cape Breton and on parts of its shores on the Gulf of St Lawrence.
At that point, however, quartz and even atmospheric air become strongly absorbent and the expensive fluorspar becomes the only medium that can be used.
It is the commercial centre of the north-western grain and wool-producing district and is also noted for its quartz and alluvial gold-mines.
It is common in mineral-veins, usually associated with quartz, and is often known to miners as "mundic."
Just as a granite is a conglomerate or mechanical mixture of distinct crystalline grains of three perfectly definite minerals, mica, quartz, and felspar, so iron and steel in their usual slowly cooled state consist of a mixture of microscopic particles of such definite quasiminerals, diametrically unlike.
To put the iron contained in iron ore into a state in which it can be used as a metal requires essentially, first its deoxidation, and second its separation from the other mineral matter, such as clay, quartz, &c., with which it is found associated.
The mountains consist here of an ancient laminated micaceous quartzite, which is in parts a flexible sandstone known as itacolumite, and in parts a conglomerate; it is interbedded with clay-slate, mica-schist, hornblende-schist and haematite-schist, and intersected by veins of quartz.
Under all these three conditions the diamond is associated with fragments of the rocks of the country and the minerals derived from them, 'especially quartz, hornstone, jasper, the polymorphous oxide of titanium (rutile, anatase and brookite), oxides and hydrates of iron (magnetite, ilmenite, haematite, limonite), oxide of tin, iron pyrites, tourmaline, garnet, xenotime, monazite, kyanite, diaspore, sphene, topaz, and several phosphates, and also gold.
African locality must be mentioned.; considerable finds were reported in 1905 and 1906 from gravels at Somabula near Gwelo in Rhodesia where the diamond is associated with chrysoberyl, corundum (both sapphire and ruby), topaz, garnet, ilmenite, staurolite, rutile, with pebbles of quartz, granite, vIII.
Among the commonest associates of the diamond are quartz, topaz, tourmaline, rutile, zircon, magnetite, garnet, spinel and other minerals which are common accessory constituents of granite, gneiss and the crystalline schists.
At Sao Joao da Chapada, in Minas Geraes, diamonds occur in a clay interstratified with the itacolumite, and are accompanied by sharp crystals of rutile and haematite in the neighbourhood of decomposed quartz veins which intersect the itacolumite.
It has been suggested that these three minerals were originally formed in the quartz veins.
A typical German find is at Taubach, near Weimar, where almond-shaped stone wedges, small flint knives, and roughly-hacked pieces of porphyry and quartz are found, together with the remains of elephants.
By modern mineralogists the name chalcedony is restricted to those kinds of silica which occur not in distinct crystals like ordinary quartz, but in concretionary, mammillated or stalactitic forms, which break with a fine splintery fracture, and display a delicate fibrous structure.
It is rather softer and less dense than crystallized quartz, its hardness being about 6.5 and its specific gravity 2.6, the difference being probably due to the presence of a small amount of opaline silica between the fibres.
Certain flat oval nodules from a decomposed lava (augite-andesite) in Uruguay present a cavity lined with quartz crystals and enclosing liquid (a weak saline solution), with a movable air-bubble, whence they are called "enhydros" or water-stones.
Their geological formation is metamorphic gneiss, veined with felspar and quartz, and interspersed with reddish porphyrite.
A simple form, which is sometimes referred to as a conical pen dulum, may be con structed with a large sewing needle carrying a galvanometer mirror, suspended by means of a silk or quartz fibre as shown in fig.
The soil of the Delta is a dark grey fine sandy soil, becoming at times almost a stiff clay by reason of the fineness of its particles, which consist almost wholly of extremely small grains of quartz with a few other minerals, and often numerous flakes of mica.
This deposit varies in thickness, as a rule, from 55 to 70 ft., at which depth it is underlain by a series of coarse and fine yellow quartz sands, with occasional pebbles, or even banks of gravel, while here and there thin beds of clay occur.
They occur as lines of dunes formed of rounded grains of quartz, and lie in the direction of the prevalent wind, usually being of small breadth as compared with their length; but in certain areas, such as that lying S.W.
The materials are quartz crystal, basalt, porphyry, syenite, granite, volcanic ash, various metamorphics, serpentine, slate, dolomite marble, alabaster, many colored marbles, saccharine marble, grey and white limestones.
The silica was needed quite pure from iron, in order to get the rich blues, and was obtained from calcined quartz pebbles; ordinary sand will only make a green frit.
Feldspar, quartz and granite are quarried in the environs.
Gold is found both in alluvial and quartz formations, the quartz being especially rich.
Auriferous quartz is worked by a foreign company in its neighbourhood.
Quartz mining began as early as 1851.
Quartz veins are very often as good at a depth of 3000 ft.
This is the region of quartz mining.
Chrysoprase, mined near Porterville and near Visalia (Tulare county), is used partly for gems, but more largely (like the vesuvianite found near Exeter, in the same county) for mosaic work; and there are ledges of fine rose quartz in the Coahuila mountains of Riverside county and near Lemon Cove, Tulare county.
Gold was discovered on the Sweetwater river in 1867, and placer and quartz deposits have been found in almost every county in the state.
The variation of the horizontal force is obtained by the motion of a magnet which is carried either by a bifilar suspension or by a fairly stiff metal wire or quartz fibre.
In the Eschenhagen pattern instrument, in which a single quartz fibre is used for the suspension, two magnets are placed in the vicinity of the suspended magnet and are so arranged that their field partly neutralizes the earth's field; thus the torsion required to hold the magnet with its axis perpendicular to the earth's field is reduced, and the arrangement permits of the sensitiveness being altered by changing the position of the deflecting magnets.
Igneous rocks are not extensively developed; in Wales they form an important feature and occur in considerable thickness; they are represented by lavas of olivine-diabase and by contemporaneous tuffs which are traversed by later granite and quartz felsite.
Minerals produced in small quantities include gypsum, millstones, salt and sandstone, and among those found but not produced (in 1902) in commercial quantities may be mentioned allanite, alum, arsenic, bismuth, carbonite, felspar, kaolin, marble, plumbago, quartz, serpentine and tin.
It generally consists of limestone, or of mixed limestone and clay, or of sand and clay, or of gravel, with here and there flint and rolled quartz.
The subsoils of some of the other districts (Cotes and St Emilion) contain much stone in the shape of flint and quartz.
The finest wines of the Medoc and Graves are largely grown on a mixture of gravel, quartz and sand with a subsoil of alios or clay.
The soil varies considerably in nature, but consists mostly of gravel, quartz, limestone and sand on the surface, and of clay and alios beneath.
In the north of Bundelkhand the prevailing rock is gneiss and quartz.
The quartz takes the shape of long serrated ridges, which are in many places a characteristic feature of the landscape.