NATURAL BOULDER OPAL

Natural Boulder Opal is a unique and striking type of opal that is known for its vibrant play-of-color and natural matrix. It is one of the most prized varieties of opal, primarily sourced from Queensland, Australia.

Key Characteristics of Natural Boulder Opal:

1. Appearance: Boulder opals are distinguished by their vibrant, iridescent colors that can include blues, greens, reds, and purples. These colors are often contrasted against the dark brown ironstone matrix in which they are naturally found.
2. Matrix: Unlike other opals that are often cut away from their host rock, boulder opals are left attached to their ironstone matrix. This results in a unique appearance where the opal's brilliant colors are set against the natural rock.
3. Formation: Boulder opals form in cracks and fissures in ironstone boulders. Over millions of years, silica-rich water seeps into these spaces and solidifies into opal.
4. Durability: Boulder opals are quite durable due to the ironstone matrix, which provides additional strength and protection to the opal itself. They rank about 5.5 to 6.5 on the Mohs scale of hardness.

Varieties of Boulder Opal:

1. Matrix Boulder Opal: This type features a more significant amount of ironstone matrix with veins or patches of opal running through it.
2. Seam Boulder Opal: This type features larger, more continuous layers of opal with less matrix visible.

Quality Factors:

1. Color: The most valuable boulder opals exhibit a vibrant and varied play-of-color. Stones with red hues are particularly prized.
2. Pattern: Unique patterns like harlequin, pinfire, and flashfire add to the stone's value.
3. Brightness: The intensity and brightness of the colors are crucial in determining the opal's value. Brighter stones are more desirable.
4. Size and Shape: Larger stones and those with an appealing shape are generally more valuable.

Uses in Jewelry:

• Design: Boulder opals are used in various types of jewelry, including rings, pendants, earrings, and bracelets. Their unique and natural look makes each piece distinctive.
• Setting: Due to their natural backing, boulder opals are often bezel-set to protect the edges and highlight the opal’s colors.