| Many minerals have been named after individuals, | | | | Prehnite is usually cut as cabochons or carved. |
| including a number of gemstones. The gemstones | | | | Specimens displaying the cat's-eye effect are |
| include Hiddenite (W.E. Hidden), Kunzite (George | | | | known but rare. Recently some green translucent |
| Frederic Kunz), Morganite (J.P. Morgan) and Zoisite | | | | to transparent material has been faceted, |
| (Sigmund Zois). | | | | producing a new look for prehnite that has |
| But there is one gemstone that has the distinction | | | | become popular for jewelry. |
| of being the very first mineral ever named after | | | | Prehnite can often by found in large sizes, |
| an individual. The gemstone Prehnite was named | | | | sometimes as large as 100 carats. It is a relatively |
| for its discoverer, Colonel Hendrik von Prehn | | | | inexpensive gem, though higher quality faceted |
| (1733-1785), a Dutch mineralogist and an early | | | | material may sell for prices approximately the |
| governor of the Cape of Good Hope colony. | | | | same as amethyst or citrine. Generally the |
| Prehnite was also the very first mineral to be | | | | faceted material is found only in smaller sizes. |
| named and described from South Africa, long | | | | Until recently, prehnite was a rare gemstone, but |
| before South Africa became an important source | | | | new deposits have made it more available. While |
| for precious gems. | | | | you are unlikely to find it in your local jewelry |
| Prehnite is a hydrated calcium aluminum silicate | | | | store, gemstone dealers often have some supply. |
| that occurs in a soft yellow-green to apple-green | | | | Deposits are found in South Africa, Australia, |
| color. Many specimens have an intriguing luminous | | | | China, Scotland and the United States. |
| quality. It has a vitreous to mother-of-pearl luster. | | | | Prehnite is said to encourages composure, |
| Prehnite is a medium-hard gem with a rating of 6 | | | | forgiveness and acceptance and is excellent for |
| to 6.5 on the Mohs scale. Most prehnite is | | | | meditation. Some people also believe that prehnite |
| translucent but transparent specimens are | | | | helps sufferers from claustrophobia. |
| sometimes found. | | | | |