Fire opal – Cabochon – Queretaro, Mexico

Fire opal, which most commonly comes from Mexico, is a specific type of mineral known for its vibrant coloration in shades of red, orange, yellow and sometimes green. These colors are caused by the presence of iron in the mineral structure of the opal. This gemstone is an amorphous silicon with a variable water content that varies between 3-10% by weight, rarely up to 21%. Mexico is a major source of fire opals, mainly thanks to the mines in the Queretaro area, which were discovered in 1835 and are still producing opals. In this area, opals are mined from volcanic rocks. Mining here takes place both at the surface and in deeper layers, which makes it possible to obtain high-quality crystals. In addition to Querétaro, there are important deposits in the states of Hidalgo, Guerrero, Michoacán, Jalisco, Chihuahua and San Luis Potosí. Smaller deposits are also found in other countries, such as Oregon in the USA, Guatemala, Australia and Canada.

Many fire opals exhibit an effect called "opalescence," which is a play of colors created by the scattering of light within the gemstone.

History and culture

Fire opals have a long history in Mexico and were prized in pre-Columbian civilizations such as the Aztecs and Mayans. These cultures considered opals to be sacred stones and used them in rituals and jewelry. In modern times, fire opals are still highly prized and are often used in luxury jewellery.

Uses

Fire opals are popular in the jewellery industry due to their beautiful colour and optical effects. They are often set in rings, earrings, necklaces and other ornaments. Because of their beauty and rarity, they are also collector's pieces.

Care and maintenance

Fire opals are sensitive to changes in temperature and humidity, which can affect their stability and appearance. Recommended:

• Avoid sudden changes in temperature.
• Do not expose opals to excessive moisture or dryness.
• Clean opals with a soft cloth and avoid chemicals that may damage the surface.