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WHAT IS IT MADE OF? Brian Lemin (Editor) Introduction
What is it made of
WHAT IS IT MADE OF?
Brian Lemin (Editor)


Introduction
From time to time questions get asked about what a particular needle work /
handwork tool is made from. These notes look at the most common confusions
and how to test which material is being used. It specifically excludes wood, as
which wood a tool is made from is for a more specialist approach than I can offer.
It is better investigated through books on the identification of wood.

Bone or Ivory.
This relates mostly to crochet hooks, tatting shuttles and lace bobbins. On the
whole crochet hooks might well be made of either but bone is more common,
tatting shuttles are more likely to be made from ivory and lace bobbins are
unlikely to made from ivory.

Firstly
there is a potentially destructive test. Basically bone "burns" Ivory does
not. Put a lighted match to the objects! Ivory will not really be effected by it. It
just goes black and you can wipe it off. ( that is unless you really subject it to a lot
of heat). Bone will have a good shot at burning and will have the flesh smell. The
object might be physically damaged by the experience.
The red hot needle test is less destructive. With this you push the red hot needle
into the object where it will not show. With bone it will enter more easily and
burn with a smell of flesh, with ivory it will be quite hard to push it in and it smells
like the burning caused by a dentists drill.
Basically it comes down to if you want to tell the differences
between bone and ivory, don't bother with hot needle or burn test. For the
person who can't visually tell the difference, the burn test is a good way
to ruin what you have.
always
assume bobbins and sewing tools are bone unless I have *very* good reason to
believe otherwise. >

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Secondly
test of the visible differences.

Basically tusks (Ivory) are teeth (incisors from the upper jaw.) They are therefore
made up of dentine as opposed to the softer material of bone.

The visible structure comprises many many minute longitudinal tubes, which
when fresh are filled with oil. It is this oil that gives it the polish and the very
gradual loss with age. Bone on the other hand is has all its "fat" boiled out before
being turned.

So, you should offer the ivory to the light and look for faint longitudinal lines and
then revolve the bobbin , very slowly, through 90 degrees. These lines should, on
revolving, become less pronounced or even disappear from the angle at which you
are observing them. (if the ivory is simulated i.e. casein based compound the
dark/light lines will remain and they are more pronounced on the simulated ivory
You will need to practice this to "see" what the description is saying.

Now to bone.

The characteristic of bone is that it is provided with a blood supply and therefore
has minute pores (which are the channels through which the bone is kept alive)
They look like tiny brown or black spots (or channels depending on the angle of
the turning.

So to sum up. Ivory has longish lines (tubes). Bone has black or brown flecks
(channels) You will need a good light source to see the lines (tubes) on ivory but
the flecks are reasonably visible with a magnifying glass in bone.

Other possibilities for Ivory are Casein type simulations or plastic. Casein will
have more pronounced parallel lines and will be visible at all light angles. Un
simulated plastic will not have the weight density neither the simulated "grain".

Other plastics chip like glass and feel warmer than true ivory
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Walrus tusk is hard to distinguish unless part of the object has a cross section of
the tusk being used. If so the core is granular dentine not hard like the true
dentine.

Main source of information was by Bly. J. Is it genuine. 1986. Mitchell Beazley.
London., but I went to the public library and surrounded myself with books on
antiques.!!!! He explained it best.


Here is another letter that I received.

Since ancient times, ivory was known, used and counterfeited too! Anyway I write
you what I know about the argument.

Ivory
I don' t know any way to distinguish between ivory from elephants, mammoth
(fossil ivory), hippopotamus and sea elephant. The only difference I know is that
ivory from hippopotamus, considered the finest, can only be used for small
objects. Another aspect is that elephant' s fang grows like tree-trunk, forming a
series of concentrical rings (not too regular, often they appear elliptical) that can
be evidenced at low magnification (10-20 x) with a good lens (or better a
stereomicroscope) and lateral light, incident from small angle. This characteristic
can be used to tell elephant's
ivory from other materials.

Artificial Ivory
The rings can be mimed, but they are too regular; there are chemical tests (using
organic solvents) that can tell the difference.

Narwhal tooth (Up to 2 m long, diameter up to 3 cm) It can only be used for long
and thin objects; generally (if the object is not too little) you can see the vascular
canal at one end of the object.

Bone and Horn
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They show (under low magnification, in the conditions of light as ivory)
several nervous and vascular canals (i.e. darker and long strips or
lines). The material is also less compact and elastic, more opaque and
not so heavy as ivory (because they are more porous).

I have microscopic photos of the materials I mentioned, but I don' t
have a scanner to send them to you.

The ""match test"" indeed is quite drastic but definitive (the smell of
burned hair, flesh or plastic is characteristic of horn, bone and
plastic).
The definitive test could be immunofluorescence with monoclonal
antibodies, but I don' t if there is a commercial source and it requires
a complex instrumentation (fluorescence microscope).

Luigi Vecchia.


Bakelite, Tortoiseshell, Horn or Plastic?
Plastic is a material capable of being molded. This covers both
synthetic and natural materials of which this report will only cover the
synthetic
The earliest synthetic plastic as celluloid discovered in mid 1850's but
developed in the early 1870 by John Wesley Hyatt from nitro-cellulose and
camphor. He hoped to find a material for billiard balls. But the celluloid he
found was too brittle, but by the end of the century was widely used for all
sorts of household items including buttons and shuttles.

Bakelite, a phenol compound was discovered by Leo Baideland in 1907.
Dr
Baekeland, in a makeshift laboratory in the back yard stable at his home in
Yonders, New York, was trying to produce a synthetic shellac. He combined
phenol (carbolic acid) with formaldehyde and found the mixture refused to be
poured from his test tube. Because he was not one to throw away a test tube, he
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was determined to clean it. But even with heat and a series of solvents, it did
not work. The material was petrified. Even though he failed to find shellac,
he was excited by what he had found, or as it turned out, the first
thermosetting plastic.

In 1910, Baekeland formed the General Bakelite Company. There are two
types of Bakelite, molded and cast. The early molded type of phenolic resin was
mixed with fillers as wood flour and asbestos for added strength which made it
dark in colour. The cast without the fillers had better decorative and colour
properties and did not require expensive molds and equipment. They were cast
in liquid form, hardened, cooled and converted to goods by machining.

Bakelite became more widely used after the patent expired in 1926 when
other firms began to improve and market it under names especially Catalin. This
newer phenol compound took colour better and was very attractive. It came from
the factory in tubes, rods and sheets of various lengths and sizes. It was then
easily worked, it could be sawed, sliced, ground, drilled, sanded and carved
into intricate shapes. it was then polished in big rolling tumblers. This is
the material we not tend to call Bakelite and it is material of some of the
most beautiful ""plastic"" buttons.

The overall industry made great gains in the 20's when a German chemist,
Hermann Standinger recognised the nature of the substances as giant molecules he
named polymers. From this, the rest of the industry developed, and there
appeared acrylics such as Lucite and plexiglass and then nylon in 1940.
This was sent to me by an Arachne member and acknowledged with thanks.

Tortoise shell

Tortoiseshell is just what it says and it was obtained in a most horrible way.
Basically the tortoise was caught and cooked (baked I think). The heat made the
shell flake off the body. This is the beautiful material we call tortoiseshell. The
tortoise was then released for a year to swim in the sea and recover. It