Expert advice on watches and jewellery
Most cultured black pearls come from Tahiti and the neighbouring islands of French Polynesia in the South Pacific Ocean, and are commonly known as Tahitian pearls. But not all black pearls are cultured. They can be freshwater pearls that have been dyed black. Look at the lustre, surface quality, colour, shape and size when judging quality.
'It refers to how sharp and brilliant the light reflected from the pearl surface is,' says Terry Chu Yin-yee, deputy director of Sotheby's China and Southeast Asia. Tahitian pearls come from a species of black-lip oysters, Pinctada margaritifera. They produce a substance called aragonite that makes up the inner lining - the mother of pearl - that's unique to Tahitian pearls, creating a moving rain- bow of colours when the pearls are examined in light. Quality Tahitian pearls should reflect light like a mirror. You should be able to see your reflection on it - and the clearer the reflection, the more lustrous the pearl.
Look for pearls with smooth, shiny surfaces with minimal spots or dimples. Bear in mind that when the pearls are cultured, flawless specimens are hard to find and, therefore, substantially more expensive. Chu suggests examining the pearls from about 2.5 centimetres when looking for imperfections.
Tahitian pearls come in a variety of colours, from metallic silver to lead and black. Within this range you'll also find blue, purple and green overtones. Black peacock pearls with a green or light pink overtone are the most valuable and sought-after in Asia. In Hong Kong, most buyers prefer Tahitian pearls to be peacock, whereas European and US buyers generally go for medium to light colours such as grey and pistachio, which are more affordable than peacock.
Size and shapes
Tahitian pearls are generally smaller than South Sea pearls. They're usually harvested after 18 months, whereas South Sea pearls are harvested after two years. Tahitian pearls begin from seven to eight millimetres in diameter, with the average measuring 10-14mm. Those that are 16mm or larger are considered rare and, therefore, valuable.
Pearls are grouped into four shapes: round, semi-round, baroque (irregularly shaped), and semi-baroque.
Chu says Asians go for the traditional round varieties, whereas Europeans and US buyers prefer less traditional shapes such as semi-round and baroque.
Buying and shopping tips
If you're investing in a necklace with matching earrings and/or rings, it's important to consider whether the lustre and colour of the pearls are consistent. It takes many years to gather a pearl necklace of considerable size with consistent lustre, surface quality, colour and shape. Experts agree that it's difficult and costly to find pearls that are spotless, especially if you're shopping for a necklace. Prices can vary dramatically, depending on the quality of the pearls and their overall consistency. After deciding how much you're ready to spend, pick a colour that you like. Try on different colours to see which one suits your complexion and style. If you have a sun-kissed complexion, black pearls with green or light blue over-tones may look best on you.
Tahitian pearls of different hues that are alternately strung on necklaces are popular, and many find the colour graduation - from light grey to black - appealing. Designs featuring other shapes are stylish alternatives besides the traditional round ones. Black cultured pearls are often featured with diamonds and precious stones in everything from necklaces to earrings, rings and brooches.
Caring for your pearls
Never expose pearls to chemicals such as hairspray, perfume and makeup. Clean by wiping them with a soft cloth that is either dry or damp, because perspiration will affect the pearl's lustre over time. Pearls are soft, so store them individually in soft pouches to prevent them from being scratched by other jewellery. Restring your necklace once a year if you wear it often.
Prince Jewellery & Watch Co, 10 Peking Rd, Tsim Sha Tsui; Chow Sang Sang, 525 Hennessy Rd, Causeway Bay, tel: 2523 8047. Many of Hodel's designs are inspired by nature and incorporate Tahitian pearls
of all shapes.
Shop 2056, IFC Mall, Central; tel: 2234 7189. The Milano collection features black cultured pearls with diamonds.
Robert Wan Tahiti
Lane Crawford, IFC Mall, Central; Lane Crawford, Ocean Terminal, Tsim Sha Tsui, tel: 2118 2888. Tahiti-based Robert Wan is one of the largest producers of black cultured pearls and counts Mikimoto as a customer.