Moonstone is such a great stone for use in claddagh rings. Moonstone comes from the mineral group known as Feldspar. Lovely iridescence is the hallmark of moonstone and moonstone is possible one of the best know varieties in the feldspar group. Labradorite is the next well know feldspar.
There is a lovely quote from Ralph Waldo Emerson. " a man is like a bit of labrador spar, which has no luster as you turn it in your hand until you come to a particular angle; then its shows deep and beautiful colors."
Iridescence and color are the appealing properties of feldspar. This iridescence is caused by scattering of light from thin layers in the the gemstone. In moonstone this is seen in blue to white. Moonstones are colorless to grey or yellow and transparent to translucent.
Moonstone appeared in Roman jewelry in 100 A.D. Even earlier examples are found in oriental jewels. Moonstone was favored by Cartier and Tiffany and appeared in their jewelry.
In India moonstone was considered as sacred. The legend in India says that if lovers place the stone in their mouth on a full moon they will see their future.
Feldspar constitute a very large proportion of metamorphic and igneous rocks. However gem varieties only occur in rare geological conditions.
Moonstones come from Sri Lanka and Burma and India. Of all the feldspars moonstone is the most valuable.
For me personally they are a joy to work with and help to create a real treasure of a claddagh ring.