Some types of gems are made as imitations of more valuable gemstones. Often, cheaper natural gems that look similar are used. For example, citrine looks like the more costly topaz. Sometimes, artificial gems are used.
‘Gemologists’ test gems and crystals to find out exactly what they are made of. They have to look closely inside the gem through a lens or a microscope. They also test the quality of light coming out of a gem and can tell whether the sapphire is artificial or natural.
Gemstones can be sandwiched together with other substances to create ‘gems’ that can be sold for more than they are really worth. This method is also used to create cheaper jewellery.
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