as to identifying fake Moroccan trilobites
bubbles in matrix and exoskeleton as signs of resins.
discover tiny holes in the matrix or the trilobite exoskeleton you can
assume you are dealing with a fake trilobite. These tiny holes, usually less
than 0,5 mm in diameter, are the results of bursting bubbles of air that
formed during the hardening process of the resin used to cast the trilobite.
A) simple fake, a Drotops trilobite completely made of resin, the cast
trilobite then mounted onto the matrix, the tiny holes in the resin surface
can be easily seen. B) magnified view of part of the axis. C) air bubbles in
the matrix of a faked Dicranurus indicate that the trilobite including
underlying false matrix has been mounted onto a piece of real rock, the
resin shows an unnatural brown color, real matrix should be of a dark grey.
differences in matrix color frequently with cast trilobites
If you find
different colors in the matrix of Devonian trilobites, for example a light
brown close to the trilobite while the rock, once you turn it over, is of a
dark grey, this indicates there may be trouble ahead. Usually the rock
is of an evenly dark grey (Hamar L’Aghdad), reddish or light yellow (Laatchana)
color. If there are differences in color as described and in addition
to that very extensive preparation marks on the surface (to hide tiny
holes), then both the trilobite and an underlying layer most likely were
cast and later mounted on some real piece of rock.
In Cambrian giant trilobites you can sometimes find color variations of the
matrix that may indicate that the specimen was assembled from different
individuals. Look for thin lines were parts may have been glued
together with their respective colors. Trilobites without tampering
should have an evenly level and colored matrix.
complete fake of a spiny Moroccan trilobite, Dicranurus monstrosus.
The trilobite plus an underlying layer were cast from brown resin and then
mounted on top of real rock. The “trilobite” was then painted, the
surrounding areas covered with preparation marks. The saw proved
it! Notice the hole underneath the “trilobite” and the color
difference between the brown resin layer on top and the real rock beneath
which is grey. Photo taken by Sonntag, sawed up by Horst Burkhard
3. crack line
in Devonian trilobites as an indication of authenticity
If you cannot
find any crack line in Devonian trilobites that can be followed on
throughout the surrounding matrix then be suspicious. These crack
lines are characteristic for authentic trilobites from the very hard rocks
of the Devonian of Morocco. It is hard to find a trilobite without
splitting it with your hammer. The absence of a crack line may be an
indication of a fake trilobite so take a close look.
4. color and
substance of the trilobite exoskeleton
exoskeleton of most Moroccan trilobites is of black, in some rare cases of
dark brown or olive color. Many faked trilobites show different colors,
often brownish, with an unnatural shine to it. Making careful use of
your front teeth, you can test the trilobite for authenticity. Fake
trilobites will feel “soft”, like plastics. This method is simple
and safe at the same time, because the nerves in your teeth are sensitive
enough to tell the difference without damaging the specimen. Authentic
trilobites are much harder than faked ones made of resin. Try it using
your toothbrush and some piece of rock. But please be careful, a
slight touch will do, don’t try and bite into it!
As far as
trilobites from the Ordovician and Cambrian of Morocco are concerned, their
exoskeleton has been replaced with hydrated iron oxides like limonite, the
color being a shade of brown or orange rather than yellow or black, as has
been seen in some faked trilobites.
these trilobites are authentic specimens, for only if you know what real
trilobites look like will you be able to identify the faked ones. The
Paralejurus on the left shows the characteristic crack lines of a Devonian
trilobite (marked by arrows), the upper one clearly visible on the cephalon,
the lower one not so obvious. Top right: clearly visible terrace lines
on the pygidium of the Paralejurus. These lines will be missing in
faked trilobites or specimens that have been treated too aggressively with a
blaster. Notice the tiny white spots, they are preparation marks
resulting from direct hits with the tip of the prep needle but of course,
they will also be gone once a blaster has been used in the manner
described. Bottom right: the individual eye lenses of trilobites of
the order Phacopida are a sign of authenticity because they are (still) hard
to fake. It should be noticed, though, that schizochroal eyes are peculiar
to the Phacopina, which are abundant in the Devonian of Morocco but of
course there are other trilobites as well (Lichida, Harpetida, Proetida).
morphological characteristics, surface details and trilobite eyes
exoskeletons of real trilobites very often show fine structures,
inconsistencies and ornamentations, there are terrace lines (see the Paralejurus
above), little knots, knobs and spines. Taking a close look at the
trilobites’ eyes will be helpful as, e.g., the Phacopina have
schizochroal eyes, the individual lenses clearly visible to the naked eye.
Faked trilobites usually lack these characteristic details … it is hard to
copy nature perfectly. Faked Phacopina usually have smooth
eye surfaces, because the production method of cast trilobites does not
allow for such details to be reproduced.
and solvents as tools to identify resin
If you are
not sure whether you are dealing with a fake trilobite a UV-light may be of
assistance. Resin reflects ultraviolet light and therefore starts
gleaming when exposed to a UV source. A real trilobite is mineralized,
it has the same reflection habits as the surrounding matrix. Be
careful, however, when testing waxed or finished trilobites like those
coming from Russia, they may start gleaming under UV light and still be
“real”. Waxing and finishing is a commonly used method to increase
contrast or conceal minor damages to the exoskeleton.
Moroccan trilobites sometimes are covered with an unidentifiable black
paste, both real specimens and faked ones. We use a solvent like
Aceton or Bindulin to remove such patinas from trilobites. Take a
paintbrush and confront your trilobite with the solvent and within seconds
the paste will come off, as do other artificial colorings. Use the
solvent on real trilobites to remove the paste and see what remains …..
perhaps not too much, if you are unlucky. If there are restored areas
they will appear white because the color came of.
ultimate and final solution – the saw!
If you are
still in doubt about the authenticity of your trilobite then saw it up with
an appropriate saw (diamond-covered blade). Is there is a hypostome
present? Bad luck - chances are you just sawed up a real trilobite!
is there a hollow area underneath the trilobite and resin has been used?
Then your trilobite was fake but it should not be necessary to saw up your
specimen unless you want to prove its lack of value 100%.
a completely faked Burmeisterella, the hole underneath the cast trilobite
can be easily seen, the use of a shiny finish to pretend a real trilobite
exoskeleton is evident. This fake was 25 cm in length. Photograph taken by
Sonntag, specimen owned and sawed up by Burkhard.