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 -- 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 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.comD. 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

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 <>) 

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). 

:  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:
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  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  

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   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

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,  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 perlarumNacre 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.) 


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.].


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