Pearl buttons

Currently, use of basic lead carbonate is limited to artificial pearls, buttons, and bijouterie. Due to the low chemical stability of this pigment and toxicity problems, it is being increasingly replaced by bismuth oxychloride and mica-based pigments. Worldwide production of basic lead carbonate pigment in 1995 was ca. 10001. 

In the back seat is Miss Muxdroozol wearing a beige, double-breasted, French hand-finished blazer with narrow-legged matching trousers. Beneath she wears a soft, saffron silk blouse with a high cossack collar and pearl buttons. 

Figure 10.4 Trodius shells natural) polished) and mother-of-pearl buttons.

Top or trochus shells, ftom the mily Trochidae, are found in the Indo-Pacific region near coral reeft. The cone-shaped top, mottled top and commercial trochus have nacreous inner layers and are used in the mother-of-pearl button industry. The shells are triangular, cone shaped, with a flat base and flattened whorls. The outer shell layer of the commercial trochus is brown and white, while the others vary in colour from red to pink and white, sometimes with splashes of brown, grey, or green (Fig. 10.4). 

Mother-of-pearl buttons can often be identified with the naked eye by looking at the back of the button, which usually retains some of the coloured layers of the trochus or other shell from which they are made. 

Pure white mother-of-pearl buttons, made from freshwater mussels, may have to be viewed under a microscope to see the aragonite platelets. Lack of these indicates a plastic imitation. 

At one time the mother-of-pearl button industry was huge indeed it was so big that it almost wiped out entire populations of freshwater mussels in North America. The industry was in turn almost kUled off by the advent of plastics. Today some buttons are still produced in the Far East and are made mostly from trochus shell. A few more exotic - and expensive - examples from other shells are also manufactured. 

On terminating his speech, the visitor scraped his foot back with disarming courtesy the foot was clad in a smart half-boot of patent leather with mother-of-pearl buttons and having done this, despite the roundness of his body, he immediately leapt backwards with the lightness of a rubber ball. 

UP casting was used in the past to produce decorative items, pearl buttons, knife and umbrella handles in attractive pastel shades, and to encapsulate parts and assemblies in the electronic industry. The most important casting application has been the manufacture of pearl buttons. The... 

The dust from mollusk shells can also provoke occupational allergies. Inhalation of mollusk shell dust in a nacre button factory was associated with h)q)ersensitivity pneumonitis (Orriols et ah, 1990, 1997). A similar case was identified in Korea (Kim et ah, 1982). Several Japanese investigators have described occupational asthma occurring among workers who culture oysters (Nakashima, 1969 Wada et ah, 1967). Exposure to dust from mofher-of-pearl in a souvenir maker (Tas, 1972) and fo cuttlefish bones in a jewelry polisher (Beltrami et ah, 1989) was linked to occupational asthma. 

Shells, pearls, and other invertebrates may be found in art and anthropology collections as worked objects, or as part of composite objects. The nacreous layer of mollusk shells is commonly referred to as Mother-of-Pearl, and may be found as inlay in objects made of wood and stone, and as small decorative and utilitarian objects such as buttons, jewelry, tool handles, and small carvings. Pearls are used most often in jewelry, drilled through so that they can be strung like beads. They are also used as decoration on fabric and objects d art. 

Natural pearls from the South Seas were Grst imported to Europe in 1845, and in 1881 the huge silver-lipped oysters were discovered in the seas around north-west Australia. In about 1900 the American ftesh-water pearl mussel industry started up. It was concentrated around the Mississippi, and b an with harvesting mother-of-pearl, most of which went to the button industry. 

In Australia there was a valuable trade in mother-of-pearl for the button industry, using the large Pinctada oyster shells found off the north-western coast. With the advent of plastic buttons in the midtwentieth century, the shell trade ceased, and another use had to be found for the shells. It was not long before Australian cultured South Sea pearls, cultured in the Pinctada oysters, appeared on the market. 

Plastic imitations of mother-of-pearl are more tricky to detect. One simulant is made by suspendir mica in a clear synthetic polymer. The effect is very realistic with an apparent play-of-colour, but the shape is often a give-away as the material is moulded. For example, a round napkin ring with no joins in the material could not be made fi m one piece of shell. Small items such as buttons are more difficult to identify. 

Wood, cork, mother of pearl, glass, or other nondurable buttons must not be used on children s clothing. Buttons should not have rough or sharp edges and must be free from rust, contamination, or any other toxic elements. Only core-spun polyester sewing thread should be used when attaching buttons. 

Mother-of-pearl is produced primarily from the shells of the freshwater species, which are boiled in alkaline water followed by soaking in fresh water. The dark surface layer is then scraped off and the shells are baked until crisp. Better grades are white, come in large pieces, and are crisp. Much of the commercial mother-of-pearl is produced from shells that are byproducts of buttons production. Major producers are the same as those of pearl (nahonal zcyx). 

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