From sparkly and shiny to mysteriously gleaming, stones used in jewelry can vary widely in terms of quality, price, color, cut and type. Stones used in jewelry making can be precious or semi-precious stones, with precious stones being harder and rarer, making them more valuable. You can also find manufactured stones, which typically are found in costume jewelry.
There are only four precious stones: diamonds, emeralds, rubies and sapphires --clear, green red and blue respectively. These stones are prized for their hardness -- measured on the Mohs hardness scale -- and are expensive because high-quality stones are rare. These stones need to be cut and polished prior to being used in jewelry and are most commonly used for special occasion or higher-end jewelry pieces.
Semi-precious stones are used for everyday jewelry, and any stone not classed as one of the four precious stones is considered semi-precious. Common stones include amethyst (purple), citrine (yellow to orange), garnet (dark red), and aquamarine (pale blue). Pearls and opals, which are milky white in color, are also considered semi-precious stones. This type is less hard than precious stones, and while generally less expensive, high-quality semi-precious stones can also be a bit pricey.
Costume jewelry is made with neither precious nor semi-precious stones. Instead, stones for costume jewelry are made with colored plastic or glass that has been shaped to resemble real stones. These are less expensive than real stones and also weigh less, making them ideal for low-cost pieces of jewelry. Manufacturing ability has improved to a point where some pieces of costume jewelry very closely resemble real stones, and designers prize these stones for their flexibility and adaptability. Because they are manufactured, they can be made to assume almost any cut, color or shape a designer desires.
Color, clarity and cut are the three primary considerations when choosing stones for jewelry -- real or otherwise. The color of the stone is the first consideration; the richness of the color, especially for precious stones, is important for valuation. The clarity of the stone refers to the degree to which the stones is transparent and naturally free of any internal or external imperfections. The cut of the stone depends on the natural shape and size of the stone. The cut will affect how reflective the stone is, determining its brilliance. Other considerations include the meanings of stones -- some are associated with birth months, while others are considered to have healing properties.