Buying Gemstone Jewellery

Buying gemstone jewellery can be fun, exciting and confusing. Whether you’re considering a gift of gemstone jewellery for someone special or as a treat for yourself, take some time to learn the terms used in the industry. Here’s some information to help you get the best quality gemstone jewellery for your money, whether you’re shopping online or in a high street jeweller's.

Natural gemstones are found in nature. Laboratory-created stones, as the name implies, are made in a laboratory. These stones, which also are referred to as laboratory-grown, created, or synthetic, have essentially the same chemical, physical and visual properties as natural gemstones.

Laboratory-created gemstones do not have the rarity of naturally coloured stones and they are less expensive than naturally mined stones. By contrast, imitation gemstones look like natural stones in appearance only, and may be glass, plastic, or simply less costly stones masquerading as other, more valuable gems, for example white sapphire could imitate diamond. Laboratory-created and imitation stones should be clearly identified as such.

Gemstones may be measured by weight, size, or both. The basic unit for weighing gemstones is the carat, which is equal to one-fifth (1/5) of a gram. Carats are divided into 100 units, called points. For example, a half-carat gemstone would weigh .50 carats or 50 points. When gemstones are measured by dimensions, the size is expressed in millimetres, for example, 7mmx5mm.

Gemstone treatments or enhancements refer to the way some gems are treated to improve their appearance or durability, or even change their colour. Many gemstones are treated in some way. The effects of some treatments may lessen or change over time and some treated stones may require special care. Some enhancements also affect the value of a stone, when measured against a comparable untreated stone. Your jeweller should tell you whether the gemstone you’re considering has been treated, especially if the treatment is not permanent, the treated stone requires special care, or the treatment significantly affects the value of the gemstone.

Some common treatments that you may be told might include:

• Heating can lighten, darken or change the colour of some gems, or improve a gemstone’s clarity.
• Irradiation can add more colour to coloured diamonds, certain other gemstones and pearls.
• Impregnating some gems with colourless oils, wax or resins makes a variety of imperfections less visible and can improve the gemstones’ clarity and appearance.
• Fracture filling hides cracks or fractures in gems by injecting colourless plastic or glass into the cracks and improves the gemstones’ appearance and durability.
• Diffusion treatment adds colour to the surface of colourless gems; the centre of the stone remains colourless
• Dyeing adds colour and improves colour uniformity in some gemstones and pearls.
• Bleaching lightens and whitens some gems, including jade and pearls.