Two-Phase inclusions and rutile needles in rock crystal from Brazil
Two-Phase inclusions and rutile needles in rock crystal from Brazil
Two-phase inclusions in sapphire, Sri Lanka
Two-phase inclusions in sapphire, Sri Lanka
Spinel crystal in dolomite marble, Burma
Spinel crystal in dolomite marble, Burma
Natural etching structure on a crystal face of diamond (trigons), polarised light
Natural etching structure on a crystal face of diamond (trigons), polarised light
Inclusions of anatase crystal and rutile fibres in rock crystal from Brazil
Inclusions of anatase crystal and rutile fibres in rock crystal from Brazil
Fluid inclusions in quartz with bituminous daughter minerals, China
Fluid inclusions in quartz with bituminous daughter minerals, China
Inclusions of hematite in aquamarine, Tanzania
Inclusions of hematite in aquamarine, Tanzania
Midge included in amber from the Baltic coast, polarised light
Midge included in amber from the Baltic coast, polarised light
 
 

The Different Types of Cultured Pearls

The white to creamy Akoya cultured pearls come from the southern sea bays of Japan and have been also been bred for several years now in the south of China and Vietnam. Their size varies between 5 and 10 millimetres and in good qualities they have a strong lustre. The most desirable colour varieties are white, pinkish-white and greenish-white.

The term "South Sea Cultured Pearls" includes, on the one hand, the white South Sea cultured pearls and on the other the grey and black, which are designated as Tahiti cultured pearls. The white South Sea cultured pearls are produced by the oyster "Pinctada Maxima", which occurs in the waters off the north coast of Australia, Indonesia, the Philippines,Thailand and Myanmar. They are treasures with a soft, velvety lustre and fascinating colours from gold to cream, white and silver grey.

The natural coloured grey to blackish green shimmering Tahitian pearls, originate in the black-lipped "Pinctada Margaritifera" oyster, which is located in the South Pacific, east of the Cook Islands and in the waters around the islands of French Polynesia.

Sizes of 8 - 20 mm in diameter, as well as the variety of shapes and the palette of enchanting natural colours combined with the typical soft lustre make the South Sea cultured pearls, whether white, grey or black, a true jewel.

Most of the freshwater cultured pearls originate from the bays and rivers of China in the Shanghai area. These pearls without nucleus are distinguished by their original shapes, their variety of colours in pastel tones and their intense lustre. Few pearls exceed 10 mm in diameter and few are perfectly round. The baroque shaped pearls are used to create exclusive attractive pearl jewellery. Today, freshwater pearls with a nucleus are also being cultivated and can reach sizes well in excess of 20 mm.

Quality and Price Criteria
The criteria for size, shape, lustre, surface texture and quality, thickness of the mother-of-pearl layer (nacre) and colour are decisive for all cultured pearls. A great deal of experience is needed to determine these quality criteria accurately.