PANAMA PEARL-SHELL, SHOWING MUD-BLISTERS, BORERS, AND PEARL
Some of these hollow shells of pearl have been found to cover small fish, lizards, etc. The writer saw one which appeared to be a large button-pearl. On lifting, it proved to be a shell of several thicknesses of nacre covering a small shell-fish about a half-inch in diameter. The imprisoned mollusk was shrunken and crumbling so that the nacreous covering could be lifted from over it, a hollow dome of pearl. Mud blisters are common in some waters and depreciate the quality of the shell and are otherwise useless. A typical mud-blister appears in the shell illustrated herewith.
The Abalone pearl occurs usually as a baroque or blister but occasionally it is found solid and spherical. Although it is not classed among true pearls, a few globular pieces found are entitled to a place among them because they are sometimes identical in construction and have a similar pearly luster, it is however very liable to crack and break and can seldom be pierced with safety.
The shell-fish from which it takes the name is the Haliotis, called here the Abalone. It is known under many names—ear-shell, Venus's ear, etc. In the English Channel Islands it is the ormer, and on the adjacent coast of France where it is very abundant the name for it is similar— "ormier." The Aelonians called it the "Ear of Venus." The shell is ear-shaped, flattened, slightly spiral and has a series of round holes near the edge curving with the last whorl toward the boss. As it grows, the oldest of these are successively filled up and the last remaining open, serves as the anal channel. The exterior is very rough and unsightly, but the mother-of-pearl interior is one of the most exquisite pieces of color work painted by the hand of nature and to this is added an enlivening iridescence most fascinating. Like it, the pearl formations are deeply tinted. Brownish reds, peacock greens, and dark grays are the prevailing colors. They are seldom of even color or luster, many of them having but one lustrous point where a pearly glaze seems to have been incorporated with the earthenware like surface.
Usually the pearls when round and lustrous are not constructed as compactly as those of the bivalves. The texture of the skins vary in quality and the frequent presence of intermediary strata of black conchiolin which shrink, makes them liable to crack and break. The blisters run very even in these two qualities of color and luster and though seldom quite as brilliant as the nacre of the shell, are very beautiful and often curiously formed. These blister-baroques are like two blisters joined at the edges, and are liable to separate there. The interior consists chiefly of black conchiolin, rough and somewhat shiny.
The "Conch" pearl, found in the Conch (Strombus gigas) of the West Indies, also is not a true pearl. The shell is used largely for ornamental purposes, especially for the cutting of cameos, and also in porcelain works. It is a large shell, sometimes weighing four or five pounds. Formerly great quantities were exported to England from the Bahamas; in one year as many as three hundred thousand. Conch pearls are devoid of nacreous luster, the surface having an appearance like china. They are slightly transparent and show under the surface a series of delicate wavy markings.
The silky sheen of these lines causes them to appear lighter than the body color of the pearl, and they seem to branch toward the surface, changing kaleidoscopically as the pearl is turned. Almost without exception the shape is ovoid, or a flattened ovoid, though some are distorted. In color they range from very pale to deep pink and coral red, the ends being usually much lighter than the body and often white. In the deeper tints they are more uniform in color, and as they are apt to be less lustrous and transparent as the shade deepens to red they show less plainly the distinguishing wavy lines, and may be easily mistaken for pieces of coral cut to the shape and polished. They are very delicate and therefore easily fractured or cracked. As the natives usually obtain the pearls by cooking the fish, for which they have a great liking, a large proportion of the few which come into the market are cracked. It is claimed also that the color fades with time. They are sometimes called "Nassau" pearls.
Pearls similar in appearance to the Conch, except that the wavy lines are absent and the skin rarely as brilliant, are taken with true pearls from the small varieties of the Avicula, especially about the coast of Venezuela. Some are white as chalk, many are tinted in various shades of gray, yellow and brownish reds. They have the shining appearance of china in different degrees, but no nacreous luster. The skins of many of these are peculiarly constructed, they show modified characteristics of various parts of the shell. The surface wave lines are present to some extent, together with curious malformations of prisms and conchiolin.
The hexagonal faces look as though they had been doubled up upon themselves together with a layer of conchiolin, the latter appearing as thick black V or U shaped marks in the faces of the distorted hexagons. Heretofore these have been considered valueless, but it is possible that with the increasing vogue of pearls and the growing desire for oddities, they will be utilized in the cheaper forms of jewelry.
Creations similar in construction to pearls are found occasionally in the common oyster and clam. Though entirely devoid of the pearly texture and luster, some of them are very perfect in shape and smoothness of skin. Whether taken from the oyster or clam they are usually called "clam pearls." The color of the oyster pearl is generally a light drab. The clam pearls are mostly purplish red or blue, often dark enough to appear black. Those taken from the oyster are generally round; those from the clam are more frequently ovoid. Occasionally one or both ends of the oval are lighter in color, as the Conch pearl is, changing there to a dark red or purple. When the color is very dark and the skin uncommonly good, they have been sold for black pearls by unscrupulous dealers. They are accounted of little value, though exceptionally large pieces will sometimes sell for as much as one hundred to a hundred and fifty dollars. Similar to these, pearly formations characterized by a glazed, or glassy, or shiny surface, are found in many molluscan varieties, bivalves and univalves, but none of these are true pearls.