Opal, a gemstone celebrated for its captivating play-of-color, holds a unique position as one of the birthstones for October. While originally the sole recognized birthstone for this month, pink tourmaline was added as an alternative in 1952. Throughout history, opal has been revered for its beauty, attributed with various powers, and occasionally shrouded in superstition. This article will delve into the history, geological origins, gemological properties, and cultural significance of this remarkable gemstone, drawing solely from available sources.
History and Lore
Opals have been treasured for millennia. Ancient Romans held the opal in high esteem, considering it the most precious of all gemstones, referring to it as opalus, meaning “precious stone.” They associated it with hope and love. Ancient Greeks believed opals could guard against disease and bestow the gift of prophecy. These early civilizations recognized the unique and alluring qualities of the stone, attributing to it both aesthetic and protective powers.
However, the opal’s reputation experienced a shift in the 19th century. A superstition arose, suggesting that wearing an opal was unlucky if it wasn’t one’s birthstone. This belief is often linked to Sir Walter Scott’s 1831 novel, Anne of Geierstein. In the story, an opal belonging to the character Anne reflected her moods, shining red when angry, blue when sad, and green when happy. Upon Anne’s death, the opal lost its color, contributing to the gem’s association with misfortune. It is important to note that this association appears to be a relatively recent development, originating in the 19th century, and not deeply rooted in ancient history.
Despite this later superstition, opals have consistently been linked to positive attributes. Throughout history, they have been credited with numerous supernatural origins and powers, and were once thought to bring good luck to their wearers. Today, opal is also recognized as the gemstone for the 14th anniversary.
Geological Formation and Sources
Opals are formed through a unique geological process. They originate as the result of seasonal rainfall in specific regions with dry ground, such as the Australian outback. The rainwater carries dissolved silica deep into ancient rock formations. As the water evaporates, these silica deposits are left behind, gradually forming opal.
The vast majority of the world’s opals are mined in Australia, which remains the most abundant source. However, significant deposits are also found in other locations, including Ethiopia, Mexico, and Brazil. Further deposits have been identified in the United States, Central Europe, Honduras, Indonesia, Madagascar, Peru, and Turkey. This widespread distribution indicates the specific geological conditions required for opal formation are not unique to Australia, though the quantity and quality of Australian opals are unparalleled.
Gemological Properties
Opals are classified into two broad categories: precious and common. The defining characteristic that separates these categories is the presence of “play-of-color” in precious opal. This phenomenon refers to the iridescent display of multiple colors when the stone is viewed in light and turned gently, creating a shimmering, rainbow-like effect. The term “opalescent” itself is derived from this characteristic.
Opal’s composition is unique among gemstones. Unlike many gems which are crystalline, opal is largely amorphous, consisting of hydrated amorphous silica (SiO2). This makes it less stable than crystalline quartz, and susceptible to deterioration over time, potentially losing its color and becoming a chalky mass of silicon dioxide.
On the Mohs hardness scale, opal ranks between 5.5 and 6.5, making it a relatively soft gemstone. This lower hardness requires careful handling to avoid scratches and damage. It is also important to avoid exposing opal to high heat or sudden temperature changes, as this can cause fracturing.
Symbolism and Metaphysical Beliefs
Throughout history, opal has been imbued with symbolic meaning. To the ancient Romans, it represented hope and love, and was associated with the goddess Venus. Ancient Greeks believed it offered protection against disease and granted prophetic abilities.
In more modern interpretations, opals are believed to possess various metaphysical properties. Some believe they can aid in emotional healing, promote creativity, and balance the heart chakra. Traditional medicine once attributed to opals the ability to detoxify, reduce fevers, alleviate eye fatigue, and calm emotional fluctuations. While these beliefs are not scientifically substantiated, they reflect the enduring cultural significance of the gemstone.
Care and Cleaning
Due to its relatively soft nature and hydrated silica composition, opal requires careful handling and cleaning. The safest method for cleaning opal jewelry is with warm, soapy water. Avoid harsh chemicals, ultrasonic cleaners, and abrasive materials, as these can damage the stone. It is crucial to avoid exposing opal to high heat or sudden temperature changes, as this can lead to cracking and loss of color. Gentle handling and proper storage will help preserve the beauty and integrity of opal jewelry for years to come.
Conclusion
Opal, with its mesmerizing play-of-color and rich history, remains a captivating gemstone. From its ancient origins as a symbol of hope and love to its more recent association with superstition, opal has consistently evoked strong emotions and beliefs. Its unique geological formation, relatively soft nature, and delicate beauty require careful handling and appreciation. As one of the birthstones for October, opal continues to be a cherished gem, representing individuality, creativity, and the vibrant spectrum of life.