Other valuable stones, the topaz, chrysolite, aquamarine amethyst and tourmaline are found.
Zircon, tourmaline, garnet and other precious stones of little commercial value are found throughout Australia.
The granite, which is intruded through the Eocene beds, is associated with a pegmatite containing tourmaline and cassiterite.
Mica, talc, chlorite, haematite), or in long blades or fibres (anthophyllite, tremolite, actinolite, tourmaline), and, when these have a well marked parallel arrangement in definite bands or folia, the rock will break far more easily along the bands than across them.
Garnet, tourmaline, staurolite, andalusite, actinolite, chloritoid or ottrelite, epidote, haematite, and if any of these is abundant its presence may be indicated by the name given the rock, e.g.
Flattened crystals of garnet, films of quartz, and needles of tourmaline are not uncommon.
These veins consist of felspar, quartz and mica, often with smaller amounts of other crystallized minerals, such as tourmaline, beryl and garnet; they are worked for mica in India, the United States (South Dakota, Colorado and Alabama), and Brazil (Goyaz, Bahia and Minas Geraes).
Throughout the world, primary deposits of tinstone are in or closely connected with granite or acid eruptive rocks of the same type, its mineral associates being tourmaline, fluorspar, topaz, wolfram and arsenical pyrites, and the invariable gangue being quartz: the only exception to this mode of occurrence is to be found in Bolivia, where the tin ore occurs intimately associated with silver ores, bismuth ores and various sulphides, whilst the gangue includes barytes and certain carbonates.
Tourmaline or rubellite is found on the borders of the Ruby Mines district and in the Shan State of Mong Long.
In other cases, especially near mineral veins, slates are filled with black needles of tourmaline or are bleached to pale grey and white colours, or are silicified and impregnated with mineral ores.
In blue tourmaline and in iolite - stones sometimes mistaken for sapphire - the dichroism is much more distinct.
Sapphires are also found in Kashmir, where they occur, associated with tourmaline, in the Zanskar range, especially near the village of Soomjam.
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.
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.
It is possible that the lyncurium of the ancients, which according to Theophrastus attracted light bodies, was tourmaline, a mineral found in Ceylon, which had been christened by the Dutch with the name of aschentrikker, or the attractor of ashes.
Giovanni Caraffa, duca di Noja (1715-1768), was led in 1758 to purchase some of the stones called tourmaline in Holland, and, assisted by L.
Hitherto nothing had been said respecting the necessity of heat to excite the tourmaline; but it was shown by Aepinus that a temperature between 992° and 212° Fahr.
He found that the electricity of the tourmaline decreased rapidly from the summits or poles towards the middle of the crystal, where it was imperceptible; and he discovered that if a tourmaline is broken into any number of fragments, each fragment, when excited, has two opposite poles.
He also found that the polarity which minerals receive from heat has a relation to the secondary forms of their crystals - the tourmaline, for example, having its resinous pole at the summit of the crystal which has three faces.
He also made many experiments with the tourmaline when cut into thin slices, and reduced to the finest powder, in which state each particle preserved its pyro-electricity; and he showed that scolezite and mesolite, even when deprived of their water of crystallization and reduced to powder, retain their property of becoming electrical by heat.
In Oxford county tourmaline, spodumene (or kunzite) and beryl occur, the tourmaline crystals being notably large and beautiful.
Many semi-precious and precious stones are found in Utah, including garnet (long sold to tourists by the Navaho Indians), amethyst, jasper, topaz, tourmaline, opal, variscite (or " Utahlite "), malachite, diopside and Smithsonite.
By adding an alcoholic solution of iodine to a solution of the sulphate in acetic acid a compound known as herapathite, 4Qu 3H 2 SO 4.2HI Ie6H 2 O, is obtained, which possesses optical properties similar to those of tourmaline; it is soluble in Iwo parts of boiling water; and its sparing solubility in cold alcohol has been utilized for estimating quinine quantitatively.
The following precious stones are reported: corundum (rubies and sapphires), beryl, topaz, zircon, garnet, amazon-stone, tourmaline, often in large crystals, and variously coloured quartz, also often found in crystals of great size.
The polarizing action of such crystals is due to the unequal absorption that they exert on polarized streams. Thus a plate of tourmaline of from I mm.
These sediments are fine and tenacious; their principal components, in addition to clay, being small grains of quartz, zircon, tourmaline, hornblende, felspar and iron compounds.
In diameter), with often felspar, tourmaline, zircon, epidote, rutile and more or less calcite.
It consists of very fine scaly kaolin, larger, shining plates of white mica, grains of quartz and particles of semi-decomposed felspar, tourmaline, zircon and other minerals, which originally formed part of the granite.
Other minerals which occur in the rocks of this group are calcite, garnet, biotite, chloritoid, epidote, tourmaline and graphite or dark carbonaceous materials.
Four series of "Researches on Heat," in the course of which he described the polarization of heat by tourmaline, by transmission through a bundle of thin mica plates inclined to the transmitted ray, and by reflection from the multiplied surfaces of a pile of mica plates placed at the polarizing angle, and also its circular polarization by two internal reflections in rhombs of rock-salt.