Category Gems & Stones

Gemstones are made from rare crystals that have been cut up and polished. They are usually hard and clear, or colourful. Gemstones are extremely valuable because of their beauty and rarity. Usually when we think of gemstones we imagine a jeweller’s shop window, or a beautiful ring or necklace. Polished gemstones are set into jewellery and decorative objects.

Hard or clear crystals are not only used to make jewellery, they are also used in factories, spacecraft and lasers.

Natural gemstones are found in the Earth. Crystals in the Earth’s rocks are called minerals. Gems made from these minerals are called natural gemstones. Artificial gemstones are made from glass and from crystals made in laboratories and factories. Gems of all kinds are often made to imitate more valuable gemstones.

Picture Credit : Google

The Earth’s rocks are moving, squashing and often melting together. It is in this turmoil that gems are formed. The rocks are a mixture of minerals which are themselves made up of chemical elements. Atoms of chemical elements, such as carbon, oxygen and silicon, join up to make tiny building blocks. These fit together in neat regular patterns to form ‘crystals’.

Exactly what type and size of crystal forms depends on the chemical elements present, the temperature of them and the pressure exerted on them. Natural gems are found as clear or coloured crystals embedded in rock. They are also found as big crystals lining cracks or cavities in the Earth’s surface layer, or ‘crust’. Some gems are washed along by rivers and may then be picked out.

How gems are formed

Some gem crystals, like garnet, grow in solid rock as it squashes beneath moving mountains. Others, such as tourmaline, are formed in veins beneath the Earth’s surface.

Stones such as agate grow in volcanic rocks at the surface. Gems like ruby grow deep down where molten rock ‘cooks’ the Earth’s crust. Diamond crystals grow way down, around 160 km beneath the surface.