Australian opal: an introduction to this highly sought-after natural gemstone

Since ancient times, opal has been among the most desired gemstones due to its unique characteristics, making its use in jewelry highly appreciated.

Among the rarest and most valuable varieties is the Boulder opal, whose distinctive appearance piques curiosity.

"Boulder" in English means rock, precisely because this gemstone is extracted along with its matrix. Some pieces are sold in their raw state, while larger or particularly iridescent ones are carefully selected by experts, cut into cabochon or faceted gemstones, and set into highly sought-after and demanded jewelry pieces.

The so-called opalescences, or the characteristic play of light and color typical of this stone, have always enchanted humans. It is impossible to remain indifferent before a gem that literally flashes blue, red, green, yellow, and purple all at once.

iven its very delicate and fragile nature, the work of artisans becomes even more complicated. They must employ all their skill and mastery to avoid fracturing the gemstone. Even the heat generated by the rotation of various tools could compromise the final result. When we have the honor of holding perfectly polished and smooth, or even better, faceted opal specimens, we must be aware of the treasure we have come into contact with.

Physical characteristics and genesis of australian opal

Australian Boulder Opal is a very rare variety of opal. It is a hydrated form of silica, specifically a silica gel with a water-rich structure that defines its gemological characteristics. Opal has a hardness ranging from 5 to 6.5, a specific gravity between 1.25 and 2.20, and an average refractive index of 1.45.

Its structure is truly unique; its micro-spherules of silica create a fascinating play of colors that has always attracted those who observe this gemstone. The diffraction of light when interacting with the internal structure of the opal makes this magnificent optical effect visible.

Opal is essentially an amorphous mineral; the term translated from Greek means "formless," and it is a very special gem because it does not have an orderly crystalline structure.

Opal has a secondary origin. Specifically, it is found as a filling of small cavities in certain volcanic rocks that are about 30 million years old.

These gems are extracted from large masses of ironstone formed underground; "boulder" in English translates to rock.

Opal, in the form of liquid silica, solidified within the cracks of these rocks and is extracted along with them as a single gem. What is obtained are fabulous cabochons or raw material pieces where the opal is encapsulated within the host rock.

The difficult access to the discovery areas and adverse climatic conditions allow for very limited extraction activity, which requires very simple and artisanal techniques, preventing the extraction of large quantities of this gem.

Polychromatic colors in australian boulder opal variety

Boulder opal is one of the many known varieties of opal, generally divided by appearance, background color, play of color, and geographical origin.

Contrary to what happens with certain gemstones, where the chemical composition itself changes with the variety, opal takes on different colors depending on the concentration of oxides present but maintains the same composition in all its varieties, namely amorphous hydrated silica.

Boulder opal has the exciting peculiarity of showing vivid color veins that contrast with the tones of the matrix, which ranges in color from yellow to brown, sometimes with touches of black.

The veins take on blue, light blue, and green tones, or lighter white and almost milky shades, within which the typical play of colors of opal is clearly visible. You can also see flashes of purple, yellow, violet, and many other colors.

Boulder opal: here is the most suitable cut

Australian Boulder Opal is characterized by high density, making it the most durable variety of opal. Like black opal, it exhibits fascinating play of colors.

The most frequently used cutting style for Australian Boulder Opal is the cabochon, one of the most suitable for showcasing its play of colors due to its surfaces: the upper one convex and the lower one flat. However, smooth spherical or even faceted cuts are also made for Australian Boulder Opal. When high-quality material is present, these are subsequently drilled to be assembled into fine jewelry such as Australian Boulder Opal necklaces.

Sometimes these gems appear in intriguing freeform shapes or even in their raw state to preserve and enhance their natural qualities.

Opal price and value of the australian boulder variety

As with most precious gems, the valuation of boulder opal depends on several factors. The size of the raw material is assessed first, followed by the presence of play-of-color patterns, which typically appear as vivid veins creating a strong contrast with the ironstone matrix. After these are noted, the tone and distribution of the play of color are evaluated.

Color is a crucial determinant and is given significant consideration; it becomes a predominant factor that can outweigh size. For example, a boulder opal gem with well-defined and extensive veins or with clearly visible areas is more valuable than one that is larger.

The cutting style also impacts the value of boulder opal. More intricate cuts, which require great attention and precision from the artisan, tend to have higher prices.

Raw Australian Boulder Opal with Freeform Matrix Shape.

However, there are no specific guidelines for determining the value of an Australian Boulder Opal. Each time, the synergy of the previously mentioned elements and their presence in a given specimen are considered.

Jewelry featuring australian boulder opal

Australian Boulder Opals, often due to the colors of their veins, tend to captivate everyone. These gems give the impression of coming from a magical realm.

The Australian Boulder Opal is undoubtedly a magnificent stone, which is why we offer numerous Australian Boulder Opal pieces in our online catalog.

We don't just provide fabulous Boulder Opal necklaces; we also offer the highest level of customization for the jewelry. Additionally, collectors can consult the section of our website dedicated to Boulder Opal gems.

For DIY enthusiasts, we suggest pairing Australian Boulder Opal gems with other elements, such as gemstones with similar or complementary hues, or gold-plated silver components. This combination will create a truly unique color contrast.

Our offerings include not only Boulder Opal jewelry but also stunning rough stones of boulder opal and prestigious gemstones of australian opal for setting, which can be integrated into magnificent jewelry designs.

Visit our site and admire them all!

Cleaning and care of boulder opal

Unlike most opal varieties, which are naturally very fragile, Australian Boulder Opal is characterized by considerable durability due to its physical properties and high iron content.

Nevertheless, taking care of this gem requires more attention compared to other gemstones. For instance, unlike precious opal, which can change color if neglected or exposed to certain conditions, Australian Boulder Opal maintains its characteristics unchanged.

It is still advisable to avoid exposing it to any type of impact.

We recommend always consulting an expert before attempting to clean an opal gem. They can guide you on the appropriate procedures to avoid damaging the stone.

For light cleaning performed occasionally, use a cloth moistened with a solution of water and a tiny amount of neutral soap without dyes or fragrances. Gently wipe the gem with this cloth.

Afterwards, rinse the gem with a cloth dampened only with water and well-wrung, and then let it air dry.

Everything about opal

The origin of its name dates back to Roman times when the Latin term "opalus" — derived from the Sanskrit "opala" — was used to describe a precious stone. Even earlier, the Greeks used the term "opallus" to refer to a stone that changed color.

In the realm of crystal therapy, opal is considered a significant gem for the benefits it is believed to offer both the body and the mind. It is thought to enhance optimism and lightheartedness and to encourage a positive outlook on life.

Moreover, many believe that opal can help rebalance energy and emotions and that it has purifying and detoxifying effects.