Fairly often on eBay there exists honest confusion about whether an item is constructed of genuine mother-of-pearl or one of the imitation plastics, especially in such items as folding hand fans, straight razors, knives, buttons, crosses and crucifixes, jewelry boxes, and women’s compacts or purses. Historically, many different nacreous shell species have been utilized in making these items, such as clam, mussel, snail, and various abalone, but here we’re specifically concerned with the fairly large and thick bivalves known as Ocean Pearl Oyster (Pinctada maxima or P. margaritifera) which are responsible for most of the white material so commonly encountered. Being able to correctly distinguish between these materials will not only help avoid problems between a seller and winning bidder, but will greatly impact the item’s final value!

There are several visual clues to look for, which are sometimes apparent even in badly taken photos:

1) The most immediately obvious are that usually in plastic there is far too much figure (the intricate and internally-patterned play of light caused by the changes in direction in the grain of the shell), and that it’s too evenly dispersed over the entire expanse of large pieces such as fan sticks and guards. Most of a raw natural pearl oyster shell is almost entirely plain or unfigured out on its large flat surface (known as the lip area), the figure being confined to the limited zone between the straight hinged edge, the notch at the top of the hinge, and the muscle scar area toward the shell’s center where the animal was attached. This natural figure is also not just randomly swirled or marbled, and does not occur in large curved arcs or have pointy geometric shapes, as seen in the plastics, but instead contains distinctively characteristic patterns such as slightly radiating fan-like fingers, bumpy-looking cloud-like figure, or fine little hammered-metal looking dimples with rather sharply defined edges to each dimple.

2) Most plastics are too glaringly, starkly white, whereas real M.O.P. is a bit softer, almost with the very slightest touch of yellow moderating the whiteness — not especially yellow-colored as such (although some shell from the Philippines and Indonesia is yellowish and in fact is known in the industry as Gold Lip or Yellow Lip), but just enough to make it the tiniest bit off-white.

3) These white plastics can also appear much more transparent than real pearl would be in the same thickness. If fan sticks are so transparent that it’s difficult to tell whether they’re in front or in back at their overlapped edges, or if detailed background or newsprint can be clearly read through the material, they’re almost certainly plastic: to be this transparent, pearl would need to be under .010″ (1/100″), far too thin to function as a fan stick or rib! However, it should be noted that some very ornately carved and pierced (or fret-sawn) M.O.P. fan sticks do have sections of their open-worked scenes which have been backed with paper-thin shell veneers (often referred to in French as burgo, burgau, or burgaudine, although technically these are terms more properly assigned to the nacreous shell of any thickness that comes specifically from the Green Sea Snail, Turbo marmoratus).

4) In plastics any apparently carved details are usually noticeably larger and thicker, sometimes verging on clumsiness, than would have been the case with similar work in real shell. This is because genuine nacre’s strength and toughness are capable of taking extremely fine work without becoming overly fragile, but the older plastics were much weaker and were thus manufactured with more massive design elements in order to avoid collapsing under their own weight, something especially noticeable in such delicate items as antique folding fans.

5) In any close-up photos of the carving or sculpting, the edges of the supposedly saw-pierced details may look too rounded, being almost perfect half-rounds rather than more vertically-sided as would have been produced using a jeweler’s saw. Also, incised lines are often far too large and soft-looking to have been done with shell-working methods or tools which would have been in use a century ago.

6) Good close-up photos may reveal the partial or entire presence of thin protruding plastic molding lines known as flash, where a tiny amount of molten plastic had squeezed out between adjacent sections of the mold, usually faintly visible around any edges. This flash in openly visible or obvious areas would usually (but not always) have been quickly cleaned off with a file, but less care was taken in obscure areas of finer detail. So, the presence of untrimmed flash is a sure indicator that an item was cast in a mold, rather than having completely hand worked detailing, even though some plastics actually were hand sawn and sculpted, as in some of the faux tortoise-shell hair combs of the period. It must be realized that when first introduced, plastics, as well as aluminum, were an exciting and expensive novelty, not just a cheap material, and found their way into some rather high-end accessories!

7) Gold used in real gilding was very precisely applied. Fake gilding, as so often encountered on fancier plastic hand fans, was painted on rather sloppily, in places going either much past or short of the outline of the particular detail being accented. Any shell or ivory worker, traditionally referred to in France as a tabletier, who was skilled enough to be working with gold would have been skilled enough to keep it inside and up to the lines! Painted details are typical of plastic items, which were hastily cranked out in mass-production shops where avoiding fussy and labor-intensive hand work was of prime importance.
The size, curvature, and useable thickness of even the largest of the wild-caught natural pearl oyster shells place severe limits on the size of flat pieces that can be taken from them. Fan sticks and guards (the two heavier and longer protective sticks to each side of a folding fan) typically range between 5?and 12?in length (not including the ribs, which support the leaf material). A 5?long single piece was possible from a large shell; anything much over that was made from multiple pieces which were carefully matched for color, figure, and reflectivity, then carefully joined together end-to-end with long overlapping bevels whose presence can easily be detected with close examination and normal eyesight. Large pieces of imitation pearl plastic are always of one piece, and will never contain this joinery.

9) Although not something that could be learned from photos, M.O.P. is quite stiff, much less flexible than plastic of the same thickness which in large thin pieces such as fan sticks would be relatively soft or springy compared to shell of the same dimension.

10) Additionally, plastics often feel slightly warmer at first touch, while harder or denser materials such as genuine shell or stone are typically slightly cooler when first handled.

In a world in which things aren’t always what they seem, it’s wise to hone our powers of observation and discernment, to be constant learners as well as active sellers and buyers, and to build a reputation as a knowledgeable professional. Best of luck in your eBay adventures!