PEARLS AND THE PEARL INDUSTRY 111 



Characteristics of Genuine Pearls from Various Sources 



Panama pearls are predominantly silver-gray in color and superficially re- 

 semble some Australian types. Australian pearls are characteristically silver-white 

 or lead-gray in color. Pearls of 100-grain weight and larger are not unusual be- 

 cause the shells in which they are found often measure 14 inches across. Pearls 

 from the Persian Gulf, Red Sea, and Ceylon waters are pinkish in color. These 

 regions supply the world with the finest pearls. The southeast coast of the Celebes 

 and Molucca Islands are famous for their black pearls. Tahiti and New Guinea 

 are other sources of fine black or greenish-black pearls. Pearls from the Gulf of 

 California are frequently of the black or greenish-black variety. In years past 

 this region was noted for pearls of this color. Venezuelan pearls have a character- 

 istically yellow cast. 



Some genuine pearls are occasionally found in the same waters in which are 

 grown Japanese cultured pearls. The genuine, as well as the cultured, have a 

 greenish-yellow color when extracted from the pearl oyster. In most instances 

 the Japanese dye their cultured pearls pink or rose to make them look hke the 

 genuine pearls obtained from the Persian Gulf. All Japanese blue, black, or 

 bronze cultured pearls have been dyed. 



Evaluation of Pearls 



Form. According to form and appearance pearls have been designated as fol- 

 lows. "Paragons": large or exceptionally beautiful; "round": perfectly spherical; 

 "button": domed on top with a flat or slightly convex back; "pear-shaped"; "drop- 

 shaped": elongated, but larger at the lower end than the true "pear-shaped" 

 pearl; "egg-shaped"; "cone-shaped": elongated, but with one flat end; "top- 

 shaped": flattened at the top, but with rounded sides; "seed-pearls": round or 

 irregular, weighing a quarter grain or even less; "dust-pearls": so small as to be 

 almost valueless; "petal pearls": rather flat, one end often being more pointed than 

 the other; "hinge pearls": found near the hinge of the shell and further differenti- 

 ated as "wing pearls" and "dog pearls", the former slightly resembling a wing, the 

 latter pointed, elongated, and narrower; "slugs": irregular and distorted, often 

 consisting of an aggregation of imperfect pearls; "hammer pearls": shaped like a 

 hammer; "baroque": having no typical form; and "half -pearls": usually made by 

 cutting off the best rounded section of an irregularly formed pearl. 



Value. As a general rule the worth of pearls may be estimated by establishing 

 a base value for a gem weighing 1 pearl grain (50 mg) and then multiplying this 

 amount by the square of the number of grains that any given pearl weighs. For 

 example, if the base value is determined to be $1, then that would be the worth 

 of a 1-grain pearl; but a 2-grain pearl would be worth 4 times as much (2x2 = 4), 

 or $4, while a 10-grain pearl would be worth $100 (10 X 10 = 100). The origin 

 of this system of valuation can be traced back to the sixteenth century, when 

 Van Linschoten learned of it in India. The base value of a pearl necklace can be 

 determined in the following way: If the center pearl weighs 25 grains, multiply 

 25 X 25, the result being 625; then take the next 2, 3, or 4 pearls, as many as 

 are of approximately the same weight, add their weights together, multiply the 

 resulting figure by itself and divide the product by the number of pearls in the 

 group. Carry out this system with the remaining pearls, grouping them according 



