Both opal and tourmaline are traditional birthstones for the astrological sign Libra, which falls from August 23 to September 22. Both gems display a variety of colors.
The most common opals are milky white with pink or green flashes of color. However, opals also come in other varieties, such as black, crystal and fire. Opals, nicknamed the "wish stone," are symbols of love, romance and happiness. Ninety-five percent of white and black opals come from Australian mines. Tourmaline comes in almost every color, which caused confusion in the past, because it was often mistaken for other gems. For instance, 16th-century explorers in Brazil believed they had found emeralds, but, in reality, they had uncovered tourmaline.