Opal - A color changing stone

 Opal: An Introduction

Opal brilliant, also known as the October Stone and the 14th and 18th Anniversary Stone, is one of nature's greatest beauties. Opal's most distinctive feature is its ability to refract and reflect specific wavelengths of light It is definitely one of the most beautiful and rare gems in the world. The word opal comes from different languages: Sanskrit upala, meaning "gem", Latin opalus, and Greek opallios, both meaning "to see a change of color".

Opal: A History

The earliest known opal artifacts have been discovered as early as 4000 BC in Ethiopia. These artifacts were later discovered in a cave in Kenya by the famous archaeologist Louis Leakey. The opal was said to have magical properties and also help its wearer see limitless possibilities. It was also thought to release inhibitions and encourage impulsivity. In the Middle Ages, opal wedding band was said to be a cure for eye diseases. Opal is also reported as a cure for blood disorders, depression, apathy, helps with reproductive organs, filters red and white blood cells and brain disorders.

Opals: How are they formed?

Opal is formed from silicate-containing waters and can be found inside any type of rock. Opal is formed from a solution of silicon dioxide and water (SiO2 + nH2O). As water flows over the ground, it picks up silica from the sandstone and carries this silica-rich solution into cracks and cavities caused by natural faults or decaying fossils. As the water evaporates, it leaves behind deposits of silica. This cycle is repeated for a very long time and eventually opal is formed. Although the water evaporates, the opal gemstone still contains 13% water.

Opal: Color

Opal can have many different colors. In its basic form, opal is colorless, but it is rarely found. The difference in color comes from the process of the water forming tiny spheres, all of which are usually uniform in size and order, bending the light in the stone to create the different colors of the rainbow. If the spheres are of random shape and arrangement, a common or colorless opal is produced.

The color of the opal depends only on the uniformity of the tiny beads. In the smaller spheres, a spectrum of blues and violets would show. In larger spheres, the colors of orange and red will show more on the stone. These stones are highly prized because they exhibit multiple "plays of color" or spectral colors when rotated.

Opal: Various types

Opal can be found in many varieties and types. Surprisingly high quality opal is rarer to find than rare rubies and emeralds. Below are the different types of opal that can be found:

Black Opal - These types of opal are the rarest and most valuable of all sterling silver opal rings. These opals usually come in rod form. Despite the name, these types of opals have the full colors of the rainbow, but the body is a dark color of black, brown, blue or gray.

Boulder Opal – These types of opals are usually found in the mining fields of Queensland, Australia. This type of opal is often cut with the ironstone left on the back because the opal seam is usually very thin. They can be found in many different forms and colors: their surface can be smooth or uneven, with the opal occurring as a solid piece on top of the ironstone, or appearing as flashing flecks of color throughout the ironstone.