Opals have always been a mysterious and fascinating gemstone. the opal has been revered for centuries. it comes in a variety of shapes and sizes, reds against blacks being the most valuable. Opals is the birthstone of October,

The fire in the opal, caused by diffraction, displays all the colors of the rainbow. Opals contain water; the quantity of the water makes the opal unique. 95% of opals are used in gemstone applications for opal jewelry, These opals are often prized for their colors and designs.

Types

There are two basic types of opal: the precious opal and the common opal. The common opal does not show any play of color. it may have partial opalescence or low defraction of light. There are dozens of opal types within these general categories. the precious opal is play of color that makes the precious opal so popular that it has been used in all types of ornamentation. those flashes of color that come out of the opal. The best opals have many different colors, in large flashes, widely dispersed across the stone. 

Function

The Romans believed opals represented purity and hope; the Greeks believed they granted their owner foresight. They were believed to be a talisman of the gods, able to ward off disease and protect their possessor from harm.

Evaluate

Opals come in a vast array of selections and settings, opals come in a vast array of selections and settings. Red, violet, yellow and orange are good colors for the display. Less valuable are blue and green, gray is not desirable.