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. Pearls similar to the pink Conch are found in the shank or chank of Ceylon (Turbinella scolymus). This is the sacred shell of the Hindus and the national emblem of Travancore in the Madras presidency, India. Vishnu carries a chank called "Devadatta" in his hand. It is said his first incarnation was for the purpose of destroying Shankhásura (the giant chank shell), and thereby regaining the Vedas, which had been stolen and taken to ocean deeps. COLOR The ideal color for a pearl is white. Although all fine white pearls show by comparison a tint of some color, a fine white must be free from an appearance which can only be described as "dark." It is not color always but a certain density which makes the gem appear dead by comparison with the soft, warm, life-like white of the perfect pearl. The layers or skins of some pearls are more transparent than others and this imparts a liveliness which is absent in the more dense. Upon looking at a string of pearls held between the eye and the light, some will appear much lighter than others and show a translucent band about one-fifth the diameter of the pearl, extending from the edge of the circumference inward. Such pearls upon examination will be found much finer in color and texture than those which have the appearance beside them of dark opaque spots when held against the light.