Mother-of-Pearl
-- See also Shell
(Fr-mère
de perle;
Ger-Perlmutt/Perlmutter;
Nor-perlemor; Rus-перламутр )
A. Mother-of-pearl. Common
sources of mother-of-pearl include the above shells, which are NOT shown at same
scale: A.abalone
(Haliotis Linnaeus, 1758 sp.),
underside
of shell (width ~16 cm)
from South Africa. (© photo
by Dave Douglass, from www.davesdowntoearthrockshop.com)
-- see also Figure B. B.trochid gastropod (Trochus niloticus
Linnaeus, 1767) with
outer layer removed (height
~10 cm) from unidentified location in South Pacific. (©
photo by Walter Spille, from www.CelebrationsCA.com).
C.
pearl oyster (Pinctada maxima
(Jameson, 1901)), one shell of
this bivalve
(greatest dimension ~19 cm) from the Philippines (© photo by R. L. "Moe" Monroe, from www.bosunlocker.com) D. yellow sandshell
mussel (Lampsilis teres
(Rafinesque, 1820)) from Illinois, U.S.A.
Note that two sizes of blanks were cut from this shell (greatest
dimension ~ 3.5 cm) in order to get the maximum number of blanks from
it. (© photo by Gary
Andrashko, Illinois State Museum, from
http://www.museum.state.il.us)
B. Mother-of-pearl. Paua or Rainbow
abalone
(Haliotis iris Martyn, 1784), an
abalone
from eastern coastal waters of New
Zealand's South Island. This shell (~10
x 16 cm)
has been fashioned to show the contrast between the original surface
and the colorful mother-of-pearl (nacre) layer. (©
photo by Rick Bromhead,
from <www.pacifictreasures.co.nz>)
DESCRIPTION: Mother-of-pearl is the designation
commonly given to the pearly
inner layer of some molluscs. This layer, typically relatively
thin, occurs in the shells of some, not all, animals of
three classes of molluscs -- Gastropoda, Bivalvia (=Pelecypoda) and
Cephalopoda. It
consists
primarily of
calcium carbonate (CaCO3),
typically aragonite (+
minor calcite), and an
organic matrix plus or minus up to two per cent water. Special
attention is directed to the fine electron micrographs of the structure
of molluscan nacre compiled by Bathurst (1971) and by Carter
(1980a).
Colors - several
colors that frequently exhibit a rainbow-like iridescence
("play of
colors") --
i.e.,
much of
it exhibits an attractive apparently moving
multicolored
appearance when surfaces are viewed as the angle
of incident light is varied. This is the characteristic
responsible
for mother-of-pearl's
wide utilization in
jewelry and decorative
pieces.
H. (effective hardness)
2½
- 4½
S.G. 2.65 - 2.84
(depending
upon sample size and method of measurement because its porosity differs
with degree of dryness, etc.)
Light transmission -
translucent to opaque
Luster - pearly to
subvitreous
Breakage - irregular to
conchoidal
Miscellaneous -
effervesces with
dilute HCl (hydrochloric
acid).
OTHER NAMES: Mother-of-pearl is
frequently referred to by the name of the mollusc shell from
which it is derived. A few of those names along with a few other
designations follow:
- abalone -
This designation -- the name of the gastropod from which a large
percentage of
mother-of-pearl is
recovered --is used rather frequently as a noun in lieu of
mother-of-pearl.
- awabi -
This Japanese term for abalone is applied rather widely both to
mother-of-pearl and the meat from these gastropods.
- Burmese
shell - name given to
a mother-of-pearl shell (otherwise not identified) from the sea around
the Mergui archipelago (Webster, 1975, p. 505)
- Manila
shell - name given to a mother-of-pearl shell (otherwise not
identified) from the Philippines (Webster, 1975, p. 505)
- nacre - a
frequently used synonym for mother-of-pearl.
- Normans
(or Norman shell) - name once applied to abalone and other
mother-of-pearl (O.E.D.).
- osmena
pearl - term applied to the nacreous layer of
chambered nautilus shells (e.g., that
used as veneer on boxes) and, unfortunately sometimes marketed as
blister pearls from the nautilus.
- paua
- designation widely applied to an abalone (Haliotis iris) that occurs
sporadically in the ocean around New Zealand (and the
Phillippines?).
- rainbow
abalone - name sometimes applied to paua shells and the nacre derived
from them.
- sea ear
(or ear shell) - name sometimes applied to abalone shells and the nacre
derived
from them.
- sea opal -
name sometimes applied to abalone because the iridescence of its
mother-of-pearl resembles opalescence.
- sedef - name
given mother-of-pearl in Anatolia (Asia Minor).
USES:
Jewelry: as the
gemstone of bracelets and watch straps, brooches and pins, cuff links,
earrings and finger rings, pendants and shirt
studs and also as hololithic rings; several of these pieces are
best described as mosaic. Flat
pieces, commonly discs are common. Some of the more attractive
pieces of jewelry feature carved or
etched mother-of-pearl (Fig. C, left). Contrariwise, some,
usually rather inexpensive, jewelry -- which to me at least
borders on the gaudy -- consist largely of mother-of-pearl that has
been dyed all sorts of colors with the resulting hues ranging from
pastel to highly saturated, the latter commonly obscuring the
material's iridescence. Webster
(1975, p. 505) notes "Some dark-coloured shell from the black
pearl oyster suitably cut, produces a cat's-eye effect, and these are
used as buttons and even mounted in jewellery."
C. Mother-of-pearl.
Left, antique
brooch (longer axis ~5 cm) with
blackened etching. (© photo
by Evelyn Phillips, from www.antiquesbyevelyn.com).
Right, "Cream mother of pearl necklace" (length - ~40 cm) with
"fingers" of mother-of-pearl strung on a cream leather cord with a
shell button closure. (©
photo
by Jackie Jones, from www.jackiejonescollection.net)
Musical instruments:
examples include marquetry on dulcimers and guitars and their
pickguards
(see Figure D in the TORTOISESHELL entry);
keys of saxophones, cornets
and other brass instruments; [and] the keys of a unique, so
far
as I have been able to determine, Steinway grand piano (Mobley's Inc.,
2006).
D.
Mother-of-pearl. Left,
pieces
of mother-of-pearl for use in marquetry (no scale indicated).
(©
photo Giovanni Aversa, from www.originalmarquetry.co.uk).
Right, "green
abalone and pink oyster mother-of-pearl"
inlay in ebony fingerboard of a guitar (horizontal lines are frets,
which serve to indicate size). (© photo Jeff Mosby, from www.mosbyguitars.com)
Ornaments:
Buttons, casings
of jack knives and pen knives,
and
handles of cutlery -- the mother-of-pearl of some bottons and handles
has been carved; parts of small carvings -- e.g., the heads and tails of bald
eagles, the bodies of which are some black material such as jet;
complete spoons, and keys of musical instruments
-- e.g., cornets and
saxophones; veneer and/or parts of inlay designs (marquetry) on
boxes (e.g., pill boxes,
jewelry
boxes and caskets), furniture (including thrones) and pistol grips,
rifle stocks and luxury muskets -- one particular musket, a parade
musket made in the 1620s in Holland and presented as a wedding gift to
the first Romanov Tsar, has literally hundreds of circular pieces of
mother-of-pearl inlaid in its stock, including the forearm portion
beneath the barrel, which in this piece includes the ramrod
housing.
In
some venues, such pieces with mother-of-pearl are
"named according to the techniques of their manufacture and according
to the region in which they are made" (Ministry...,1986):
Examples noted include
Istanbul Work, Damascus Work, Vienna Work and Jerusalem
Work. One of the more
interesting uses of these buttons (etc.) is their role that serves to
characterize the rather ornate clothes that are worn by the "Pearly
Kings and Queens," a group that is widely recognized for
its charitable activities in London, England. These so-decorated
clothes are said to be based on a suit that Henry Croft, a street
sweeper, created in the late 1800s to direct attention on his efforts
to raise funds for less fortunate people of the city. Indeed,
Pearl buttons are said to have covered much of the material of that
suit.
Miscellany: Some
shells that exhibit
especially attractive mother-of-pearl
surfaces -- e.g., abalones,
paua shells, turban shells and nautili -- are collection "show pieces"
and exhibited in cases and on "whatnots" and in other
prominent places
in many
homes.
Two materials are of special note
here: Abalam
and mosaic abalone,
both of which are laminates. Abalam (a Nabisco-like
designation
-- Abalone + laminate) consists of
relatively thin ( ~.3 mm)
nacreous layers -- each of which, when cut, can be flattened without
breaking. These layers are laminated with epoxy cement as the
binder. The
number of layers is determined by the thickness specified by the
user,
usually for inlay work. The term abalam is
also given laminates, which consist of abalone mother-of-pearl plus an
unidentified material, that are used for inlays (Luthers..., nd).
[Incidentally,
Abalam is also recorded as the name of "a King of Hell and
one of Paimon's assistants, who
will attend him if some offerings are made to his demon chief."
(Wikipedia, 2005)].
Mosaic abalone consists of small pieces of
abalone, including paua, apparently recovered from small shells
(and/or, I suspect, broken "leftovers" of larger shells) that are
laminated
for use as, for example, knife handles (Mother of..., nd,
"Mosaic abalone"). In
addition, Mother-of-pearl, as "Small, hand-cut
shapes with straight edges, called
'tesserae', are glued to a fiberglass
mesh ... [to make] a lightweight material that offers a seamless
installation [for creating, for example, mosaics], and there is no
limit to the sheet size. [Consequently,] Mother of pearl
sheets may be used on interior floors, exterior and interior walls,
countertops, doors and ceilings. [Also,] Insertion into architectural
elements,
such as columns or furniture is easily accomplished"
(Wikipedia, 2006). Three
techniques that involve use of such mother-of-pearl are referred
to as the inlaying, gluing and paste methods -- see Ministry... (1986).
Anyone
interested in additional, some rather exotic, uses should look at the
short article by Wilkie (2000) and the included photographs of Joshua
McHugh.
OCCURRENCES
& NOTEWORTHY LOCALITIES:
The
sources of mother-of-pearl, which has
been recovered from
both marine and freshwater molluscs, have changed with time. The
following are representative.
Most abalone (Haliotis Linnaeus, 1758 sp.) occur near-shore -- i.e., from the
intertidal zone to depths of about 200 feet. Today, much of the
abalone of the mother-of-pearl on the market comes from coastal waters
along
the southern tip and Western Cape region of South Africa.
Unfortunately, this
abalone, which is prized for its food value as well as a source for
mother-or-pearl, has recently been the focus of "an armed battle to
save the country's abalone stocks from extinction at the hands of
poachers and international smuggling syndicates." (Marshall,
2002.) Two other noteworthy sources of
mother-of-pearl are the Trochid[ae]
gastropods (e.g., Trochus niloticus
Linnaeus,
1767 ) from shallow
coastal waters
off
some of the South Pacific islands (e.g.,
the Solomon Islands and
Bougainville, Fiji, New Caledonia and The Federal States of Micronesia)
and the "pearl oyster" Pteriid[ae]
bivalves -- e.g., Pinctada margaritifera (Linnaeus,
1758) of the Pacific and Pinctada maxima (Jameson, 1901)
of the tropical seas off, for example, Asia, the
Philippines and Australia.
During
the first
half of the 20th century, mussels
(e.g., Fusconaia ebena (I.
Lea,
1831))
dug from
tributaries
of the Mississippi -- e.g., the Fox, Illinois
and Ohio rivers -- were the basis of
a mother-of-pearl button industry that was centered near the
Mississippi River along the
Illinois-Iowa border. These clams provided
the raw material; blanks were cut in several towns within the
region -- e.g.,
Cairo and Naples, Illinois; [and] most of the marketed
buttons were
finished in Muscatine, Iowa. The industry apparently
prospered until the late 1940s when plastic buttons and zippers took
over the market (Edlen, nd).)
E. Mother-of-pearl. Antique
buttons from the first half of the 20th century. Collection of
Sara Hopp. (©
photo
by Sara Hopp, www.mantofev.com).
See also Figure A/D.
REMARKS:
The
designation mother-of-pearl apparently
came into English early in the 16th century via a translation of
the Middle Latin mater
perlarum.
Nacre is from Old French nacle,
from
Old Italian naccaro (now nacchera) drum,
possibly from Arabic naqqārah (Harper,
2001...; see also the
rather long discourse about this in O.E.D.) Strictly an aside: I am
told that some
"wags" in the biology profession find it hilarious to relate the
generic name for abalones (Haliotis)
to halitosis.
The outer layers of shells are removed to get to and then "harvest" the
nacreous mother-of-pearl -- see Figure B. Once recovered, the
mother-of-pearl is either used as such -- which is true of most of that
from paua shells -- or, in
the case of some of the less colorful shells, dyed.
Mother-of-pearl
is rather easily dyed -- typically only tinted so the iridescence is
not masked -- to virtually any color; these products are
usually described
by adding color indicators -- such as red, pink, orange, golden, green,
aqua,
magenta and even black -- as adjectives to mother-of-pearl in the
market place. The previously mentioned inlaying, gluing and paste
techniques are described in Antika
(The Turkish Journal of
Collectable Art) -- see Ministry...
(1986).
Mother-of-pearl
has a long history and diverse lore with
the documentation of that lore ranging
from good to virtually nonexistent. Much of the recorded
information has been repeated in several publications.
Two examples follow:
According to the
American Museum of Natural History(nd),
"Throughout history, certain cultures have placed little or no value on
pearls and have focused instead on luminescent mother-of-pearl from
mollusk shells. Before the 19th century, Japanese shell divers who
found pearls apparently did not bother to keep them. Polynesian
children are said at one time to have used pearls as marbles.
[Contrariwise,] These and
other peoples harvested pearl oysters for their shells, using the
mother-of-pearl for decoration. Abalone was also popular with many
groups, including those in the Americas: people ate the flesh of the
mollusks and used pieces of colorful abalone shell as inlay on carved
objects made of wood, ivory and bone."
When
unearthed by archeologists, "The tombs ... of Sumerian
royalty from ancient Mesopotamia ... yielded ... several
beautiful wooden ornaments and musical instruments inlaid with Mother
of Pearl, that illustrated just how sophisticated this
ancient culture actually was. The Silver
lyre of Ur, found in one of the graves in the Royal Cemetery, dates
back to between 2600 and 2400 B.C. Miraculously well persevered,
the
lyre was entirely covered in sheet silver
and inlaid with Mother of Pearl. The silver cow's head decorating the
front has inlaid eyes of shell and lapis lazuli, and the edges, borders
and plaques of the sound box are
inlaid with Mother of Pearl." (SilverShake, nd)
The
resilience of nacre is superior to that of man-made composite materials
such as cermets. This appears to manifest the arrangement of the
constituent aragonite micro-grains of aragonite and the pliant
proteins, an arrangement that is analogous to that of bricks and
mortar, respectively. Consequently, materials science researchers
have investigated
this
natural composite, because its resilience was
superior to that of human-made ceramics.
In recording the results of an apparently successful procedure for
producing such materials, Tang et
al.
(2003) noted that "Finding a synthetic pathway to artificial analogs of
nacre and bones represents a fundamental milestone in the development
of composite materials."
The
designation
mother-of-pearl has also been applied to other animals and
phenomena. Three examples are the mother-of-pearl wing moth (Pleuroptya ruralis (Scopoli, 1763)) of
the British
Isles -- for a photo, see Hlasek (nd); the mother-of-pearl
butterfly (Salamis augustina Boisduval,
1833 ssp. vinsoni Le Cerf),
now extinct, formerly of Mauritania -- for a photo, see Vane-Wright
(2003, p.102); and mother-of-pearl clouds, from the Norwegian perlemorskyer
(H. Mohn
1893), which
are stratosphere
clouds that "have been seen most often in Norway (but
occasionally also in Scotland, Iceland and Alaska), and then only in
the months between November and March." (O.E.D.)
SIMULANTS:
Crocodile wood - see
Satin wood (on this list), which is the more commonly used designation
for this
material when
it is substituted for mother-or-pearl.
***Glass - Opaline
glass, in particular, is sometimes marketed as a mother-of-pearl
substitute.
- [Macroscopic examination should suffice.].
***Plastics
- Diverse plastics have virtually, albeit not completely,
replaced mother-of-pearl so far as its use as the raw material for
making buttons, and the "Synthetic
key touches [on, for example, saxophones and cornets, many of which are
now] made of Pyralin
or similar imitation materials have
been "affectionately" referred to as mother
of toilet seat
by
musicians (Wikipedia, 2006).
- [Macroscopic examination should suffice.].
Satin
wood (Zanthoxylum
rhetsa (Roxb.)
DC. -- Synonym, Fagara rhetsa Roxb.)
- This
wood, also called cabrit and sometimes called
Crocodile
wood, is frequently referred to as the
"Ivory of Woods." It is used in
marquetry in lieu
of mother-of-pearl, which it roughly resembles (Macdonald, 2006). -
[Macroscopic
examination should suffice.].
REPLICAS:
N/A.
R.V.
Dietrich © 2015
Last update:
20 July 2012
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