Page:The New International Encyclopædia 1st ed. v. 13.djvu/61

* MARBELLA. iron. f.'rain. sugar, cork, and fisli. Population, in HIOO, 9075. MARBLE (OF. marble, marbrc, Fr. marhrc, Prnv. niiiniif, uKirbrc, from J^at. nuinnor, niarblo, from (JU. lidpfiapos, muniKirvs, bright stone, inarblo, from /iapftalpeiv, murmiiircin, to sparkle). In a strict sense a crystalline limestone having a granular structure. The term has, however, become broadened as a result of commercial use and now includes any limestone, either crystalline or non-crystalline, Avliich will take a polish, ilarbles vary considerably in their texture and color. Some ai-e extremely fine-grained, like those of Vermont, while others are coarsely granular, as in New York State. Those oom- j)0sed entirely of carbonate of lime are pure white, but many are colored gray or blue by car- bonaceous matter, while others exhibit beautiful shades of pink, yellow, red, and brown, due to iron compounds. The presence of fossil remains may also add to their beauty. JIarbles are usually found in regions of metamorphic rocks (see t^EOLOGY), and hence the rock has been at limes subjected to crushing forces. These have developed fissures in the rock, which subsequently became filled by foreign mineral matter, and it is to this that much of the beautiful marking or veining of many ornamental marbles is due. ilarble occurs in many geological formations, but in the United States it is obtained mostly from the Paleozoic rocks. The best-known de- posits arc found in the Eastern States. In west- ern Vermont, at West Rutland, Proctor. Bran- don, and other localities, some of the quarries have reached a depth of 400 feet, and contain many grades, varying from the purest white statuary marble to the gray, or 'true blue' variety, as it is called. Vermont supplies 80 per cent, of the marble used for monumental wcuk in the L'nited States. A fine-grained, white, dolomitie marble is quarried at Lee. in western Massachusetts, and also near Pittsfield. Much nuirble for structural work is obtained from Saint Lawrence and Westchester counties. N. Y. ; from Cockeysville. Md., and Pickens County. Ga. These are all magnesian marbles of coarsely crystalline character. Black marble was at one time quar- ried near Glens Falls. N. Y. ; and at Swanton, Vt., there occurs a deposit of variegated marble much used for wainscoting and floors. Some of the varieties found here resemble imported marbles. About CO per cent, of the marble used in the L'nited States for furniture tops and in- terior decoration is obtained from near Knox- ville. Tenn. The colors are variegated, but chiefly vcinings and niottlings in red, brown, pink, and gra.y. Aside from these areas, marble of white and gray striping is quarried in Tnyo Gount.v, Cal. Two types which have attracted some attention are the serpentine or verde an- tiques found in eastern Pennsylvania, and the onyx marbles from Arizona. Colorado, and Cali- fornia. These latter are not true onyx, but a. travertine, composed of carbonate of lime, and formed in caves or around calcareous springs. Many ornamental marbles are imported into tile United States from various Eurojiean coun- tries. .mong the more important types are: Uliirk (jiu! Golrl. a black Italian limestone veined with yellow; Brornlrjlr. a light yellow marble with red cloudings, obtained from the Pyrenees; Carrara, the white marbles quarried at Carrara, Italy; GiaUo antico, a yellow marble much 41 MARBLE. suugiit after by the ancient Greeks and Romans; and (Iriollc, a bright red variety, obtained in the Pyrenees. The last named is also found at Swanton. Vt. Landscape marble is a variety con- taining coloring matter dispersed through it in such a manner as to resemble a landscape. Xero antico is a greenish-black .serpentine marble; Sumidian marble is an African variety, often of yellow color; I'arian, a white nuirble much used liy the ancient (irecks and obtained from the island of Paros; PcntelUe is another white nuirble used by the ancient Greeks, weurring near Athens; Rosso antico, a red marble; iS'i'rna, a yellowish marble, often with veins or patches of gray or purple. The most famous marble known to the ancients was the Parian marble, which was a finely granu- lar and very durable stone, of waxy appearance when polished. Some of the finest Grecian sculp- tures were formed of this marble, among them being the Venus de' iledici. The Pentellic marble was at one time preferred bv the Greeks to Parian, because it was whiter and finer grained. The Parthenon was entirely built of it. It does not resist the weather well. The quarries at Carrara were known to the ancients, but their chief importance has been in modern times. The temple of Jupiter Serapis near Naples was constructed of a gray streaked micaceous marble, much used by the ancients and known as cipo- lino. Marble suitable for structural work sells at from $1.50 to $4 per cubic foot, while statuary marble brings .$12 or $15 j^er cubic foot. Marble must commonly meet certain requirements as to strength, color, texture, freedom from flaws, and durability in the open air. Its crushing strength is commonly from 10,000 to 12,000 pounds per square inch. The opening of a marble quarry is usually expensive and attended with financial risks, as a thickness of from 10 to 30 feet of rock usually has to be taken ofl' before sound marble is reached. After a sufficient area of surface has been pre- pared b,v the removal of the imperfect stone, channeling machines, which may be either per- cussion or diamond drills, are set to work, and rectangularl,y crossed channels are cut to a desired depth, say from 5 to 7 feet. One of the blocks, called the key block, is then broken oflf at the base by wedgin.g and lifted out with a crane. This gives ready access to the others, which are then drilled as circumstances may require, the quarry being worked out in floors. The blocks removed commonly run 4 feet 6 inches by 6 feet 6 inches, but much larger ones are sometimes extracted on special demand. The marble after quarrying is taken to the mill and sawed into blocks or slabs, or chiseled into mon- umental pieces. The first smoothing is done with sand and water, but the final polishing with a mixture of putty powder and weak acid rubbed on with a flannel-covered revolving bufTcr. The total value of marble produced annually in the United States exceeds $4,000,000. BinuonRAPiiT. Merrill. Stones for Building and Decoration : id.. "Mineral Resources." United States f'lcoloijical Siirrci/ (Washington, annual) ; McCallie. "Marbles of (Jeorgia," in Gcorpia Clen- logical Snrretj : Hopkins. "Report on Marbles." Arkansas Oeolopical Snrvei/. vol. iv. (1800); Ries, '"Limestones and Marbles of Western New- England," Seventeenth Annual Report United