Some about jet:
JET
by Mae Williams
There is evidence that jet was mined many hundreds of years
before the birth of Christ. That jet was known to the ancients,
both in England and elsewhere, is proved by the fact that
ornaments of jet have been found with Paleolithic remains in
Switzerland, in Celtic barrows, and Roman coffins. Jet was
thought to have protective powers and used as a talisman like
amber. The Greeks used powdered jet as a remedy for toothache and
believed it to be a preventative of evil influences. The Greeks
and Romans knew jet under the name of “gagates”. The derivation
seems to come from the river Gages where Pliny wrote that the
material originally was found. In early times, jet was collected
in the same way that Baltic amber was obtained, that is, by
picking up drift pieces from the sea shore. The chief supply no
doubt originated from the deposits near Whitby in Yorkshire,
England. In the 1870=92s, there were 200 workshops employing
hundreds of workers in the Whitby jet area where some of the
finest material was mined. Although its use is of antiquity, its
popularity gradually declined. The lack of good material and
skilled labor did little to encourage the industry, only a few
work the mines today. Jet is really a kind of fossilized coal, or
brown lignite which has formed over thousands of years. It
usually occurs in shales, often as compact masses. A bad
conductor of heat, jet feels warm to the touch. Friction develops
electricity, and heat will cause it to burn. Rough jet is
covered by a rind that is removed by chipping with a large
chisel. The pieces are then ground or carved into the desired
shape. Jet can be turned on a lathe when freshly mined. The
qualities required in jet are a hardness of 3 to 4, a homogeneous
material with a conchoidal fracture, a uniform black color, and
there must be no foreign material present such as iron pyrites.
Many articles were made of jet. Rings, bracelets, beads,
rosaries, crucifixes, candlesticks and inkstands. A demand for
old jewelry of the Victorian age has brought out of hiding fine
pieces of jet where it has been hidden for years. Perhaps, it was
unwanted and discarded, but today it is regaining its place in
the jewelry trade.