Collection: Brown opal

Brown opal is formed by ancient clay deposits containing silica. Over millennia, silica-rich solutions penetrate these deposits, creating an environment conducive to the formation of brown opal. In addition, hydrothermal processes promote the deposition of silicon dioxide in the cavities present in the clay. Silica microspheres form, creating the characteristic porous structure of opal.

So, brown opal belongs to the class of silicon dioxides with a significant iron and manganese content, which gives it its characteristic brown hue. These metallic impurities, combined with the basic chemical composition, greatly influence the physical and optical properties of brown opal.

Brown opal has a play of color that is much more subtle than that of white or black opals. This optical phenomenon is known as iridescence, resulting from the diffraction of light through silica microspheres present in the opal's structure. The presence of various inclusions can also contribute to the variety of colors observed.

Brown opal is amorphous, meaning it lacks an ordered crystalline structure. Instead, it consists of randomly arranged microscopic silica particles. Its color ranges from light to dark brown. Brown opal has a hardness of between 5.5 and 6 on the Mohs scale, making it softer than many gemstones. For comparison, diamond has a hardness of 10, the highest on the Mohs scale.

In Australian Aboriginal culture, brown opal is considered a sacred stone. It is said to have been created when the Creator, after descending on a rainbow to bring peace, left behind traces of the rainbow's colors. These traces then transformed into opals of all colors.

In medieval Europe, opal was associated with mystical and magical powers, granting its possessor gifts of premonition and clairvoyance. However, these beliefs were sometimes contradicted by superstitions, which portrayed opals as evil talismans due to their changeable nature and play of color.

In Hindu tradition, brown opal is often associated with the goddess of fortune, Lakshmi. This stone is said to have been born from the tears of happiness of this goddess. It is said to attract wealth and prosperity to those who wear it.

The main deposits are located in Australia (Lightning Ridge and Coober Pedy), Madagascar, Hungary, Mexico and Slovakia.