
October’s Birthstone: Opal
The birthstone for October is the opal, which are prized for their iridescent and ever-changing appearance. Opals are often used in jewelry, including rings, earrings, and pendants, to showcase their vibrant colors. Opals are unique gemstones known for their stunning play-of-color, which can include a wide range of hues like blues, greens, pinks, and yellows. Play-of-color is defined as "a pseudo chromatic optical effect resulting in flashes of colored light from certain minerals, as they are turned in white light." The internal structure of precious opal causes it to diffract light, resulting in play-of-color. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque, and the background color may be white, black, or nearly any color of the visual spectrum. Black opal is considered the rarest, while white, gray, and green opals are the most common.
The name opal is believed to be derived from the Sanskrit word upala (उपल), which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος). It has been reported that...