Online Encyclopedia

BARYTES

Online Encyclopedia
Originally appearing in Volume V03, Page 456 of the 1911 Encyclopedia Britannica.
Spread the word: del.icio.us del.icio.us it!

BARYTES  , a widely distributed

See also:
mineral composed of barium sulphate (BaSO4) . Its most striking feature and the one from which it derives its name barytes, barite (from the Greek Oapvs, heavy) or heavy spar, is its
See also:
weight . Its specific gravity of 4.5 is about twice as
See also:
great as that of salt and of many other colourless, transparent and glassy minerals not unlike barytes in general appearance . The mineral is usually found in a state of consider-able chemical purity, though small amounts of strontium and calcium sulphates may isomorphously replace the barium sulphate: ammonium sulphate is also sometimes
See also:
present, whilstclay,
See also:
silica, bituminous
See also:
matter, &c., may be enclosed as impurities . Crystals of barytes are orthorhombic and isomorphous with the strontium and lead sulphates (celestite and anglesite) ; they are usually very perfectly
See also:
developed and present great variety of form . The simplest are rhomb-shaped tables (fig . 1) bounded by the two faces of the basal pinacoid (c) and the four faces of the prism (m); the angle between the prism-faces (mm) is 78° 23', whilst that between c and m is 9o° . The mineral has a very perfect cleavage parallel to the faces c and m, and the cleavage surfaces are perfectly smooth and bright . The crystals of prismatic habit represented in
See also:
figs . 2 and 3 are bounded by the domes d and f and the basal pinacoid c; fig . 4 is a plan of a still A%:: ~ .~ Gw --------------------- more complex crystal . Twinning is represented only by twin-lamellae, which are parallel to the planes m and f and are of secondary origin, having been produced by pressure .

Crystals of barytes may be transparent and colourless, or

white and opaque, or of a yellow, brown, bluish or greenish colour . Well developed crystals are extremely
See also:
common, but the mineral occurs also in a granular, earthy, or stalactitic condition . It is known as cawk in the
See also:
Derbyshire lead mines . The " crested " or " cock's comb " barytes occurs as rounded aggregations of thin lamellar crystals . Barytes is of common occurrence in metalliferous
See also:
veins, especially those which yield ores of lead and
See also:
silver; some of the largest and most perfect crystals of colourless barytes were obtained from the lead mines near Duf ton in Westmorland . It is found also in beds of iron ore, and the haematite mines of the Cleator
See also:
Moor
See also:
district in west Cumberland have yielded many extremely
See also:
fine crystals, specimens of which may be seen in all mineral collections . In the neighbourhood of Nottingham, and other places in the Midlands, barytes forms a cementing material in the Triassic sandstones;
See also:
amber-coloured crystals of the same mineral are found in the fuller's earth at Nutfield in Surrey; and the septarian nodules in
See also:
London Clay contain crystals of barytes as well as of
See also:
calcite . Crystals are found as a rarity in the amygdaloidal cavities of igneous rocks . Artificially prepared crystals of barytes may be obtained by allowing a solution of a soluble barium salt to diffuse slowly into a solution of a soluble sulphate . Barium chloride is present in some natural waters, and when this is the case the interaction of sulphates results in a deposition of barytes, as has occurred in the pipes and
See also:
water-boxes of the Newcastle-on-
See also:
Tyne
See also:
coal mines . Commercially, barytes is used in the preparation of barium compounds, as a
See also:
body for certain kinds of paper and
See also:
cloth, and as a white pigment (" permanent white ") . The finely powdered and washed mineral is too crystalline and consequently of insufficient opacity to be used alone as a paint, and is therefore mixed with " white lead," of which material it is also used as an adulterant .

(L . J .

End of Article: BARYTES
[back]
ANTOINE LOUIS BARYE (1796-1895)
[next]
BARYTOCALCITE

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click and select "copy." Paste it into a website, email, or other HTML document.