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LABRADORITE, or LABRADOR SPAR

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Originally appearing in Volume V16, Page 30 of the 1911 Encyclopedia Britannica.
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LABRADORITE, or LABRADOR SPAR , a See also:lime-soda See also:felspar of the See also:plagioclase (q.v.) See also:group, often cut and polished as an ornamental See also:stone. It takes its name from the See also:coast of Labrador, where it was discovered, as boulders, by the Moravian See also:Mission about 1770, and specimens were soon afterwards sent to the secretary in See also:London, the Rev. B. See also:Latrobe. The felspar itself is generally of a dull See also:grey See also:colour, with a rather greasy lustre, but many specimens exhibit in certain directions a magnificent of See also:low, rounded hills, seldom rising more than 500 It. above the surrounding See also:general level. Minerals.—The See also:mineral See also:wealth is undeveloped. Thick beds of excellent See also:iron ore See also:cover large areas in the interior and along the shores of See also:Hudson and See also:Ungava Bays. Large areas of mineralized Huronian rocks have also been discovered, similar to areas in other parts of See also:Canada, where they contain valuable deposits of See also:gold, See also:copper, See also:nickel and See also:lead ; See also:good prospects of these metals have been found. See also:Climate.—The climate ranges from See also:cold temperate on the See also:southern coasts to See also:arctic on Hudson Strait, and is generally so rigorous that it is doubtful if the See also:country is See also:fit for See also:agriculture See also:north of 51°, except on the low grounds near the coast. On See also:James See also:Bay good crops of potatoes and other roots are grown at Fort See also:George, 540 N., while about the See also:head of See also:Hamilton Inlet, on the See also:east coast, and in nearly the same See also:latitude, similar crops are easily cultivated. On the See also:outer coasts the climate is more rigorous, being affected by the floating See also:ice See also:borne southwards on the Arctic current. In the interior at Mistassini, 50° 30' N , a See also:crop of potatoes is raised annually, but they rarely mature.

No attempts at agriculture have been made elsewhere inland. Owing to the See also:

absence of grass plains, there is little likelihood that it will ever be a grazing See also:district. There are only two seasons in the interior: See also:winter begins See also:early in See also:October, with the freezing of the small lakes, and lasts until the See also:middle of See also:June, when the ice on See also:rivers and lakes melts and summer suddenly bursts forth. From unconnected observations the lowest temperatures of the interior range from -50° F. to -6o° F., and are slightly higher along the coast. The mean summer temperature of the interior is about 55° F., with frosts during every See also:month in the See also:northern portion. On the See also:Atlantic coast and in Hudson Bay the larger bays freeze.solid between the 1st and 15th of See also:December, and these coasts remain ice-See also:bound until See also:late in June. Hudson Strait is usually sufficiently open for See also:navigation about the loth of See also:July. Vegetation.—The southern See also:half is included in the sub-Arctic See also:forest See also:belt, and nine See also:species of trees constitute the whole arborescent See also:flora of this region; these species are the See also:white See also:birch, See also:poplar, See also:aspen, See also:cedar. Banksian See also:pine, white and See also:black spruce, See also:balsam See also:fir and See also:larch. The forest is continuous over the southern portion to 53° N., the only exceptions being the summits of rocky hills and the outer islands of the Atlantic and Hudson Bay, while the low margins and See also:river valleys contain much valuable See also:timber. To the northward the See also:size and number of barren areas rapidly increase, so that in 55° N. more than half the country is treeless, and two degrees farther north the limit of trees is reached, leaving, to the northward, only barrens covered with low Arctic flowering See also:plants, sedges and See also:lichens. See also:Fisheries.

—The fisheries along the shores of the Gulf of St See also:

Lawrence and of the Atlantic See also:form practically the only See also:industry of the white See also:population scattered along the coasts, as well as of a large proportion of the inhabitants of See also:Newfoundland. The See also:census (1891) of Newfoundland gave 10,478 men, 2081 See also:women and 828 See also:children employed in the Labrador See also:fishery in 861 vessels, of which the See also:tonnage amounted to 33,689; the See also:total catch being 488,788 quintals of See also:cod, 12i5 tierces of See also:salmon and 3828 barrels of See also:herring, which, compared with the customs returns for 188o, showed an increase of cod and decreases of salmon and herring. The salmon fishery along the Atlantic coast is now very small, the decrease being probably due to excessive use of cod-traps. The cod fishery is now carried on along the entire Atlantic coast and into the eastern See also:part of Ungava Bay, where excellent catches have been made since 1893. The See also:annual value of the fisheries on the See also:Canadian portion of the coast is about $350,000. The fisheries of Hudson Bay and of the interior are wholly undeveloped, though both the bay and the large lakes of the interior are well stocked with several species of excellent See also:fish, including Arctic See also:trout, See also:brook trout, See also:lake trout, white fish, See also:sturgeon and cod. Population. The population is approximately 14,500, or about one See also:person to every 35 sq. m.; it is made up of 3500 See also:Indians, 2000 See also:Eskimo and goon whites. The last are confined to the coasts and to the Hudson Bay See also:Company's trading posts of the interior. On the Atlantic coast they are largely immigrants from Newfoundland, together with descendants of See also:English fishermen and Hudson Bay Company's servants. To the north of Hamilton Inlet they.are of more or less mixed See also:blood from See also:marriage with Eskimo women. The Newfoundland census of toot gave 3634 as the number of permanent white residents along the Atlantic coast, and the Canadian census (1891) gave a white population of J728, mostly See also:French Canadians, scattered along the north See also:shore of the Gulf of St Lawrence, while the whites living at the inland posts did not exceed fifty persons.

It is difficult to give more than a rough approximation of the number of the native population, owing to their habits of roving from one trading See also:

post to another, and the consequent liability of counting the same See also:family several times if the returns are computed from the books of the various posts, the only available data for an enumeration. The following estimate is arrived See also:play of See also:colours—See also:blue, See also:green, See also:orange, See also:purple or red; the colour in some specimens changing when the stone is viewed in different directions. This See also:optical effect, known sometimes as " labradorescence," seems due in some cases to the presence of See also:minute laminae of certain minerals, like See also:gothite or See also:haematite, arranged darallel to the See also:surface which reflects the colour; but in other cases it may be caused not so much by inclusions as by a delicate lamellar structure in the felspar. An See also:aventurine effect is produced by the presence of microscopic enclosures. The See also:original labradorite was found in the neighbourhood of Nain, notably in a See also:lagoon about 50 M. inland, and in St See also:Paul's See also:Island. Here it occurs with See also:hypersthene, of a See also:rich bronzy sheen, forming a coarse-grained norite. When wet, the stones are remarkably brilliant, and have been called by the natives " See also:fire rocks." See also:Russia has also yielded chatoyant labradorite, especially near See also:Kiev and in See also:Finland; a See also:fine blue labradorite has been brought from See also:Queensland; and the mineral is also known in several localities in the See also:United States, as at Keeseville, in See also:Essex See also:county, New See also:York. The ornamental stone from See also:south See also:Norway, now largely used as a decorative material in See also:architecture, owes its beauty to a felspar with a blue opalescence, often called labradorite, but really a See also:kind of See also:orthoclase which See also:Professor W. C. See also:Brogger has termed cryptoperthite, whilst the See also:rock in which it occurs is an See also:augite-See also:syenite called by him laurvigite, from its See also:chief locality, See also:Laurvik in Norway. See also:Common labradorite, without play of colour, is an important constituent of such rocks as See also:gabbro, See also:diorite, See also:andesite, See also:dolerite and See also:basalt. (See PLAGIOCLASE.) Ejected crystals of labradorite are found on Monti See also:Rossi, a See also:double parasitic See also:cone on See also:Etna.

The See also:

term labradorite is unfortunately used also as a rock-name, having been applied by See also:Fouque and See also:Levy to a group of basic rocks rich in augite and poor in See also:olivine. (F. W.

End of Article: LABRADORITE, or LABRADOR SPAR

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