Most people think the coral used in jewelry comes from South Pacific coral reefs such as the Great Barrier Reef off Australia. However, these coral reefs are formed by a different species than the coral that is traditionally used in jewelry. Most jewelry coral is found in the Mediterranean Sea or in the Pacific near Japan and Taiwan. It grows in ocean colonies of branches that look like underwater trees, and is found in a range of colors, including pale pink (called angelskin coral), orange, red (called noble coral), white and black. The most valued colors are deep red, black and pink. It is much softer than other gems, with a hardness of only 3.5 on the Mohs Scale. In jewelry-making, coral is often carved into beads or cameos, or can be left and polished in its natural branch-like form.

Among the most ancient of gem materials, coral has been used for adornment since prehistoric times. While coral inlays and ornaments have been found in Celtic tombs from the Iron Age, the gem also has a history of religious significance. It is one of the seven treasures in Buddhist scriptures, and coral rosaries are used by Tibetan Lamas.

Coral was long thought to be a powerful talisman that could stop bleeding, protect from evil spirits, and ward off hurricanes. Because it was believed that coral protected the wearer, it was a traditional gift to children. Coral was also believed to lose its powers once broken. Today, coral is the traditional 35th anniversary gift for married couples.

Earring Back Types

Butterfly Back: A double looped piece resembling a butterfly that fits over a post. Variations on this design are called push back clasps. The basic post and butterfly back are usually used for stud earrings and lighter weight drop earrings.

Hinged Snap Backs: This clasp features a hinged post that snaps into a groove on the back of the earring. It is commonly found on hoops. Sometimes the hinged post is curved to provide more room to fit around the ear, sometimes called a saddleback.

Hook Backs: This earring backing is simply a long, bent post that fits through the piercing. Hooks have several variations, most notably the shepherd's hook and the French hook. While thin wire hooks reduce the weight of long earrings, making them more comfortable, they aren't as secure as other clasp styles.

Lever Back: A hinged lever snaps shut against the curved post to form a closed loop around the ear lobe. This clasp is very secure and good for large or medium sized styles that drop just below the ear.

Omega: Also called French clips, this clasp has a straight post and a looped lever. The hinged lever closes around the post and is held against the ear with pressure. The omega clasp is the most secure clasp, especially for the larger, heavier earrings.

Screw back: This backing is a slight variation of the standard post and butterfly nut back. Instead of pushing on the back, the nut twists onto the threaded post. A screw back post design is often preferred for expensive diamond stud earrings that require increased security.