Abalone pearls have the irregular surface and coloring of the haliotis. Conch pearls resemble the delicate pink china-like lining of the shell, and clam pearls have the glazed earthenware appearance of the inside of a clam shell. The one material difference between a pearl and the lining of the shell in which it grows is, that in the one case the fish deposits the nacre over an even surface, and in the other wraps it around a central point with delicate precision in successive filmy layers. Dissection shows that a pearl during growth is liable to many mishaps. As with the human creature, a promising youth may end in a wretched maturity. It is also possible that an ugly period may be redeemed by later happenings, and the thing that was worthless in its early existence, be found in its age worthy of a place among the great gems. Pearls found with a dull, chalky exterior sometimes have lustrous skins beneath. Sometimes a bony-looking formation will be found, on breaking it, to have a variety of skins in the interior, some of which are very lustrous, others white and chalky, like the middle shell of the mollusk. Many of these dead pearls are formed throughout of this material. Others, perfectly spherical, are simply successive layers of prism groups like the conchiolin plates of the shell. Upon cutting these through the centre the skins are shown by the concentric rings marking their divisions and the prismatic formation appears as glistening lines radiating from the nucleus to the surface. Under the microscope these layers, which are thicker than the nacreous skins of true pearls, appear identical with the epidermis plates, except that they are concentric instead of flat, and are free from the coarse, rough, conchiolin deposit which forms the extreme outer coating of the shells. This deposit is also found, however, in some pearl formations, as many of the abalone baroques, especially when they are somewhat flat in shape, are like two pearl blisters joined, with the shell-building process reversed, the rough, black conchiolin being inside, and the nacre outside. Undoubtedly pearls containing hidden qualities which made them once gems are thrown away as valueless, while others found just as nature had covered their earlier coarseness with a coat of beauty, are worn and excite much admiration for their skin-deep beauty. Though the successive skins of a pearl do not usually vary much in color, except in abalone pearls, it does happen occasionally, for the removal of dark yellow skins sometimes discloses another of better color—a good pink for instance. From the sectional appearance of pearls it seems probable, that in the majority of cases the color of yellow pearls would be improved by the removal of the outer waves of the outer skin.