A Hand-book of Precious StonesRothschild, Meyer D.
Science
A Hand-book of Precious Stones
Rothschild, Meyer D.
Precious stones
Cyanite is found in Switzerland, the Tyrol, Styria, Carinthia, Bohemia,
Norway, Finland, France, South America, Scotland, Ireland, Siberia, the
East Indies, and the United States. Clean specimens are not plentiful,
and fine blue pieces have frequently been sold for sapphires. The
cyanite can be distinguished from the sapphire by its inferior hardness
and lighter weight.
LAPIS LAZULI.
Lapis lazuli, the sapphire of the ancients, is a mineral, translucent
to opaque, ranging in color from colorless to an azure-blue,
violet-blue, green, and red.
The principal color, however, is a rich, azure blue, sometimes shading
into green, and having a vitreous to greasy lustre.
Its hardness is 5 to 5.5, specific gravity 2.38 to 2.42; it is
decomposed by muriatic acid, and fuses before the blow-pipe to a white
glass. It is rarely found clean, but has usually a number of veins and
spots of a metallic nature. It is composed of:
Silica 45.
Alumina 31.76
Soda 9.09
Lime 3.52
Sulphuric acid 5.89
and traces of iron, soda, and potash.
This mineral is found in Siberia, Transylvania, Persia, China, Thibet,
Tartary, South America, India, and Brazil.
Lapis lazuli is sometimes employed for jewelry, and was for some
centuries ground up and used to make the mineral paint known as genuine
ultramarine. This paint is now produced chemically, and the more costly
mineral compound is rarely used.
The imitation of lapis lazuli for jewelry purposes is also very easy,
as metal filings can be readily introduced into the azure blue glass,
and thus an imitation of the genuine stone produced, which is perfect
excepting in hardness.
HIDDENITE.
The hiddenite is a variety of spodumene that has only been found in one
locality, namely, Alexander County, North Carolina. This mineral was
discovered by W. E. Hidden, and has been named after him.
The hiddenite is perfectly transparent, and varies from a pale
yellowish- to a deep emerald-green, being very brilliant, and
approaching the emerald in color. As this stone is rarely found large
enough for cutting into gems, it is highly prized, and good specimens
command a large price.
The hardness of the hiddenite is 6.5 to 7, and specific gravity 3.13
to 3.19; before the blow-pipe it melts to a clear glass, and it is
attacked by salts of phosphorus. It is composed of:
Silica 64.35
Alumina 26.58
Lithia 7.05
with traces of iron and soda.
SPODUMENE.
Spodumene is sometimes cut and polished as a gem, but its peculiar
cleavage makes it a bad stone for the lapidary to cut and the jeweler
to mount.
Its hardness is 6.5 to 7, specific gravity 3.13 to 3.19, and lustre,
vitreous to pearly.
Grayish-green, greenish-white, and sometimes yellow or faint red are
the colors. Its composition is:
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account