Other precious stones, including the sapphire, emerald, oriental emerald, ruby, opal, amethyst, garnet, chrysolite, topaz, cairngorm, onyx, zircon, &c., have been found in the gold and tin bearing drifts and river gravels in numerous localities throughout the states.
On exposure to a high temperature, the sapphire usually loses colour, but, unlike ruby, it does not regain it on cooling.
Sapphire is widely distributed through the gold-bearing drifts of Victoria, New South Wales and Queensland, but the blue colour of the Australian stones is usually dark, and it is notable that green tints are not infrequent.
Bordas, the blue colour of sapphire exposed to the action of radium changes to green and then to yellow.
According to lapidaries the hardness of sapphire slightly exceeds that of ruby, and it is also rather denser.
Purple corundum, or sapphire of amethystine tint, is called Oriental amethyst, but this expression is often applied by jewellers to fine examples of the ordinary amethystine quartz, even when not derived from Eastern sources.
The colour of the normal sapphire varies from the palest blue to deep indigo, the most esteemed tint being that of the blue cornflower.
O - &lrcecpos, but there seems no doubt that this term, like the Hebrew sapir of the Old Testament, was formerly applied to what is now called lapis lazuli; the modern sapphire was probably known as baKCveos (hyacinthus).
In blue tourmaline and in iolite - stones sometimes mistaken for sapphire - the dichroism is much more distinct.
The blue colour in sapphire has been variously referred to the presence of oxides of chromium, iron or titanium, whilst an organic origin has also been suggested.
Verneuil succeeded in imparting a sapphire-blue colour to artificial alumina by addition of i 5% of magnetic oxide of iron and o.
Under artificial illumination many sapphires appear dark and inky, whilst in some cases the blue changes to a violet, so that the sapphire seems to be transformed to an amethyst.
Coarse sapphire is found in many parts of the United States, and the mineral occurs of gem quality in North Carolina and Montana.
The rolled crystals of sapphire occur, with garnet and other minerals, in glacial deposits, and have probably been derived from dykes of igneous rocks, like andesite and lamprophyre.
The sapphire occurs also in Europe, being found in the Iserweise of Bohemia and in the basalt of the Rhine valley and of Le-Puy-en-Velay in France, but the European stones have no interest as gems.
Hence clear colourless corundum is known as white sapphire or "leucosapphire."
White topaz is sometimes called "water-sapphire," a name which should, however, be restricted to iolite (q.v.).
Sapphirine is a rare mineral, not related to sapphire except in colour.
The mica card is generally mounted on a brass framework, F F, with a brass cap, C, fitted with a sapphire centre and carrying four magnetized needles, N, N, N, N, as in fig.
C, aluminium cap with sapphire centre; N, N', needles; P, pivot stem with pivot.
Silk threads to a central disk of aluminium, in the centre of which is a round hole designed to receive an aluminium cap with a highly polished sapphire centre worked to the form of an open cone.
The badges of the other four classes are round plaques, the first three with indented edges, the last plain; in the second class the dragons are in silver on a yellow and gold ground, the jewel is a cut coral; the grades differ in the colour, shape, &c., of the borders and indentations; in the third class the dragons are gold, the ground green, the jewel a sapphire; in the fourth the silver dragons are on a blue ground, the jewel a lapis lazuli; in the fifth green dragons on a silver ground, the jewel a pearl.
African locality must be mentioned.; considerable finds were reported in 1905 and 1906 from gravels at Somabula near Gwelo in Rhodesia where the diamond is associated with chrysoberyl, corundum (both sapphire and ruby), topaz, garnet, ilmenite, staurolite, rutile, with pebbles of quartz, granite, vIII.
The Anakie sapphire-fields of Queensland are situated near Anakie station on the Central railway, to the west of Emerald and east of the Drummond Range.
(For figure of crystal of sapphire see Corundum and for artificial sapphire see GEM, § Artificial.) The so-called "Hope sapphires" of trade have been shown to be artificial blue spinets, coloured by cobalt.
R, Sapphire cap.
The button which distinguishes the first grade is a transparent red stone; the second grade, a red coral button; the third, a sapphire; the fourth, a blue opaque stone; the fifth, a crystal button; the sixth, an opaque white shell button; the seventh, a plain gold button; the eighth, a worked gold button; and the ninth, a worked silver button.