What is the difference between Precious and Semi-Precious Stones?

Precious generally describes the most valuable stones. These stones are usually transparent, faceted, with a hardness of 8 or higher. This means they are great stones for durability in jewelry. This category includes diamonds and what are known as the colored stones. Well known colored stones are rubies, emeralds, sapphires, etc. It also includes lesser known stones such as tanzanite, tsavorite, and indicolite. There are exceptions of course. Opal is neither transparent, nor faceted, and it has a hardness of 5.5. Natural Pearls are not transparent either, and they are the only stone always left natural, not cut, when set in jewelry.

Semi-precious is the classification for all other stones. This includes most translucent or opaque stones. Semi-precious stones usually have a hardness of 7 of less. Some can be very soft. Most semi-precious stones are cut into cabochons. A cabochon is usually flat or slightly domed on the bottom, and domed on top. The world of cabochons has really expanded lately with cabochons being cut into all different shapes, and some even being sculpted or carved. Semi-precious stones include agates and jaspers. Agate stones and Jasper stones come from all over the world, in many colors and patterns. They have a hardness of 7-which is still good for durability while wearing in jewelry. The softer stones, such as Malachite as a 4, must be treated with care when setting, cleaning, and wearing, as they can scratch easily.