|
See also: EMERY (Ger. Smirgel) , an impure variety of See also:corundum, much used as an abrasive See also:agent. It was known to the Greeks under the name of vµbptr or vµipts, which is defined by Dioscorides as a See also:- STONE
- STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
- STONE, CHARLES POMEROY (1824-1887)
- STONE, EDWARD JAMES (1831-1897)
- STONE, FRANK (1800-1859)
- STONE, GEORGE (1708—1764)
- STONE, LUCY [BLACKWELL] (1818-1893)
- STONE, MARCUS (184o— )
- STONE, NICHOLAS (1586-1647)
stone used in See also:gem-See also:engraving. The See also:Hebrew word shamir (related to the See also:Egyptian asmir), where translated in our versions
of the Old Testament " See also:adamant " and " See also:diamond," probably signified the emery-stone or corundum.
Emery occurs as a granular or massive, dark-coloured, dense substance, having much the See also:appearance of an See also:iron-ore. Its specific gravity varies with its See also:composition from 3'7 to 4.3. Under the See also:microscope, it is seen to be a See also:mechanical aggregate of corundum, usually in grains or See also:minute crystals of a bluish See also:colour, with See also:magnetite, which also is granular and crystalline. Other iron oxides, like See also:haematite and See also:limonite, may be See also:present as alteration-products of the magnetite. Some of the alumina and iron See also:oxide may occasionally be chemically combined, so as to See also:form an iron See also:spinel, or hercynite. In addition to these minerals emery sometimes contains See also:quartz, See also:mica, See also:tourmaline, cassiterite,
&c. Indeed emery may be regarded as a See also:rock rather than a definite See also:mineral See also:species.
The hardness of emery is about 8, whereas that of pure corundum is 9. The " abrasive See also: power," or " effective hardness," of emery is by no means proportional to the amount of alumina which it contains, but seems rather to depend on its See also:physical
See also:condition. Thus, taking the effective hardness of See also:sapphire as Iota, Dr J. See also:- LAWRENCE
- LAWRENCE (LAURENTIUS, LORENZO), ST
- LAWRENCE, AMOS (1786—1852)
- LAWRENCE, AMOS ADAMS (1814–1886)
- LAWRENCE, GEORGE ALFRED (1827–1876)
- LAWRENCE, JOHN LAIRD MAIR LAWRENCE, 1ST BARON (1811-1879)
- LAWRENCE, SIR HENRY MONTGOMERY (1806–1857)
- LAWRENCE, SIR THOMAS (1769–1830)
- LAWRENCE, STRINGER (1697–1775)
Lawrence See also:- SMITH
- SMITH, ADAM (1723–1790)
- SMITH, ALEXANDER (183o-1867)
- SMITH, ANDREW JACKSON (1815-1897)
- SMITH, CHARLES EMORY (1842–1908)
- SMITH, CHARLES FERGUSON (1807–1862)
- SMITH, CHARLOTTE (1749-1806)
- SMITH, COLVIN (1795—1875)
- SMITH, EDMUND KIRBY (1824-1893)
- SMITH, G
- SMITH, GEORGE (1789-1846)
- SMITH, GEORGE (184o-1876)
- SMITH, GEORGE ADAM (1856- )
- SMITH, GERRIT (1797–1874)
- SMITH, GOLDWIN (1823-191o)
- SMITH, HENRY BOYNTON (1815-1877)
- SMITH, HENRY JOHN STEPHEN (1826-1883)
- SMITH, HENRY PRESERVED (1847– )
- SMITH, JAMES (1775–1839)
- SMITH, JOHN (1579-1631)
- SMITH, JOHN RAPHAEL (1752–1812)
- SMITH, JOSEPH, JR
- SMITH, MORGAN LEWIS (1822–1874)
- SMITH, RICHARD BAIRD (1818-1861)
- SMITH, ROBERT (1689-1768)
- SMITH, SIR HENRY GEORGE WAKELYN
- SMITH, SIR THOMAS (1513-1577)
- SMITH, SIR WILLIAM (1813-1893)
- SMITH, SIR WILLIAM SIDNEY (1764-1840)
- SMITH, SYDNEY (1771-1845)
- SMITH, THOMAS SOUTHWOOD (1788-1861)
- SMITH, WILLIAM (1769-1839)
- SMITH, WILLIAM (c. 1730-1819)
- SMITH, WILLIAM (fl. 1596)
- SMITH, WILLIAM FARRAR (1824—1903)
- SMITH, WILLIAM HENRY (1808—1872)
- SMITH, WILLIAM HENRY (1825—1891)
- SMITH, WILLIAM ROBERTSON (1846-'894)
Smith found that the emery of See also:Samos with 70.10% of alumina had a corresponding hardness of 56; that of See also:Naxos, with 68.53 of Al203, a hardness of 46; and that of Gumach with 77.82 of Al203, a hardness of 47.
Emery has been worked from a very remote See also:period in the Isle of Naxos, one of the See also:Cyclades, whence the stone was called naxium by See also:Pliny and other See also:Roman writers. The mineral occurs as loose blocks and as lenticular masses or irregular beds in granular See also:limestone, associated with crystalline See also:schists. The Naxos emery has been described by See also:Professor G. Tschermak. From a chemical See also:analysis of a See also:sample it has been calculated that the emery contained 52.4% of corundum, 32.1 of magnetite, 11'5 of tourmaline, 2 of See also:muscovite and 2 of margarite.
Important deposits of corundum were discovered in See also:Asia See also:Minor by J. Lawrence Smith, when investigating See also:Turkish mineral resources about 1847. The See also:chief See also:sources of emery there are Gumach Dagh, a See also:mountain about 12 M. E. of See also:Ephesus; Kula, near See also:Ala-shehr; and the mines in the hills between Thyra and Cosbonnar, See also:south of See also:Smyrna. The occurrence is similar to that in Naxos. The emery is found as detached blocks in a reddish See also: soil, and as rounded masses embedded in a crystalline limestone associated with mica-schist, See also:gneiss and See also:granite. The proportion of corundum in this emery is said to vary from 37 to 57%. Emery is worked at several localities in the See also:United States, especially near See also:Chester, in See also:Hampden See also:county, See also:Mass., where it is associated with peridotites. The corundum and magnetite are regarded by Dr J. H. See also:Pratt as basic segregations from an igneous magma. The deposits were discovered by H. S. See also:Lucas in 1864.
The hardness and toughness of emery render it difficult to See also:work, but it may be extracted from the rock by See also:blasting in holes bored with diamond drills. In the See also:East See also:fire-setting is employed. The emery after being broken up is carefully picked by See also: hand, and then ground or stamped, and separated into grades by See also:wire See also:sieves. The higher grades are prepared by washing and eleutriation, the finest being known as " See also:flour of emery." A very See also:fine emery dust is collected in the stamping See also:room, where it is deposited after floating in the See also:air. The fine See also:powder is used by lapidaries and See also:plate-See also:glass manufacturers. Emery-wheels are made by consolidating the powdered mineral with an agglutinating See also:medium like shellac or silicate of soda or vulcanized See also:india-See also:rubber. Such wheels are not only used by dentists and lapidaries but are employed on a large See also:scale in mechanical workshops for grinding, shaping and polishing See also:steel. Emery-sticks, emery-See also:cloth and emery-See also:paper are made by coating the several materials with powdered emery mixed with See also:glue, or other adhesive See also:media. (See CORUNDUM.) (F. W. R.
End of Article: EMERY (Ger. Smirgel)
Additional information and Comments
There are no comments yet for this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.
Links to articles and home page are always encouraged.
|
del.icio.us it!