One finds occasionally in lots, a mock-pearl which has been cut and polished from the mother-of-pearl, but imitations of this character are scarce and find no place in the market. The few made are found usually in parcels of fresh-water pearls and are put there by unscrupulous dealers, as also are hematite balls and even buckshot, to be sold with the lot by weight as genuine pearls.

Since the price of pearls has advanced so rapidly, much ingenuity has been shown in the improvement of poor pearls. Button pearls grown to the shell are broken out and the under or flat side carefully scraped and smoothed to hide the irregular lines of juncture between the pearl and the shell. Protuberances on the surface of round pearls are scraped off and the broken skin edges smoothed down so as to be unnoticeable to the naked eye.

In a like manner chalky rings and spots are toned down. Surface cracks are filled by soaking the pearls in a solution and if the pearl has been pierced, interior cracks can also be rendered unobservable. A serious objection to pierced pearls arises from the ease with which interior defects can be doctored where the skin is pierced and a boring made through the nacreous layers. Not only are cracks made to disappear, but coloring matter can be introduced between the skins. A white pearl of very poor color can by such means be changed temporarily into a black pearl which will command a fancy price. This illegitimate doctoring of pearls, whereby defects are hidden and a fictitious appearance of quality imparted to last long enough to make sales at exorbitant prices, should not be confounded with the legitimate improvement of pearls which is now growing to be an industry of some importance. Experts are now able by careful manipulation to restore to some extent the luster which has been lost by wear or age.

Formerly this was done by skinning the pearl, i.e., removing the outer skin by peeling it carefully off with the edge of a sharp knife, an unsatisfactory method at best, as the under skin may not be good and if all the outer skin is not taken off, the broken edges of the layers composing the skin, mar the luster and color when the pearl is worn. Few also succeed in removing a skin without scratching the new one disclosed by its removal.

Pearls having a decidedly bad outer skin with a good one under it, can only be materially improved by removing the bad skin, but owing to the liability of finding equally bad imperfections underneath, or irregularities which would necessitate the removal of several skins with a consequent loss of size and weight, pearls with minor imperfections or lack of luster are now slowly rubbed between the fingers, the abrasion being assisted by various substances which differ with the judgment and experience of the operator, the preparation being in all cases kept secret by the expert using it. Many fine pearls which have lost their pristine luster are now considerably improved by this method, and without the dangers involved and the necessary loss of weight, consequent on peeling.

Large numbers of poor or imperfect pearls are scraped or otherwise doctored by the traders and speculators at the fisheries. These men acquire such pearls at a slight cost, and by various methods fix them so that by mixing them in lots with good pearls, they often make large profits. They also mix in many cracked pearls. This is done more often at Margarita and the other Venezuelan fisheries where the proportion of cracked pearls is greater than in the Indian and South Sea fisheries.

The skins of a pearl may also be removed by the application of weak acids, but this method requires careful and expert handling or the acid will act irregularly and leave the surface, if improved in luster, uneven and pitted.

Few important fresh-water baroques and irregular pearls leave the west without receiving the attention of the speculators through whose hands they pass, and the scraping is often very roughly done. Rough and discolored projections are broken or filed off and then scraped over with a knife edge. While fresh, the broken skin edges left thus will often pass unnoticed by a careless buyer, but they become discolored and dead later. Unless one buys of a dealer in whom implicit confidence may be placed, not alone for honesty but for his knowledge of pearls, it is better to examine all pearls under a glass before purchasing.

As many persons both in the trade and out of it, are not sufficiently familiar with pearls to be quite sure of their ability to detect the genuine from fine imitations, the following points of difference will be of service. All imitation pearls made of some solid material are heavier than the genuine and lack the pearly characteristics of the fine imitations even. If made of solid glass without acid finish, they are shiny and too poor to require a second consideration, if acid finished they have a "ground-glass" appearance which is unmistakable. If made of other material of a vitreous nature, they are heavier than pearls, dull in luster or without luster, dark in color and unmistakably lacking in pearly characteristics. The only dangerous imitations are the Japan culture pearls and the hollow, glass bead-pearls. The former may always be recognized by the mother-of-pearl back, the latter by various signs.