Black opal features deep gray to ink-black body color, making it the most prized variety in the opal family. The dark background enhances its vibrant play-of-color, ranging from reds to purples. However, not all black opals are equally valuable. The highest value is attributed to specimens displaying a full spectrum of colors with intense brightness.
White opal, with its lighter body color, can be categorized into milky and crystal varieties based on transparency. While white opals are generally less valuable than black opals due to higher production, some high-quality crystal opals, distinguished by their purity, transparency, and rich play-of-color, command significant value.
Matrix opal forms when opal fills the tiny voids within host rocks, creating an interwoven structure with the surrounding rock.
Naturally occurring within host rocks, ironstone opal derives its name from the iron-rich minerals found in its formation. The complex and diverse shapes of ironstone opals, often cut along their vein patterns, result in unique and irregular surfaces.
Fire opal originates from ancient volcanic eruptions, typically found in sedimentary rock formations or volcanic fissures. Its distinct colors, ranging from orange to red, are attributed to trace amounts of iron oxide. While high-quality fire opals with excellent transparency and play-of-color command high prices, most orange-red fire opals are cut into faceted gemstones for enhanced brilliance.
🌏 **Origins**
- **Australia:** The primary source of opals globally, with approximately 90% of natural opals originating from this region. Notable opal mining areas include Lightning Ridge in New South Wales for black opals, South Australia for white opals, and Western Queensland for ironstone opals.
- **Mexico:** Main producer of fire opals.
- **Other Origins:** Ethiopia, Brazil, United States, among others.
