Welo Black Opal

Appearance: They exhibit vibrant, multi-color fire including red, green, blue, and orange against a dark, sometimes gray or brown, background.
Hydrophane Property: Welo opals are usually hydrophane, meaning they absorb water, which can change their transparency and make colors brighter temporarily.
Treatments: While naturally dark, many Welo black opals are treated using heat or smoke to darken the base color for higher contrast.
Patterns: They can show diverse patterns, with "honeycomb" and "patchwork" being highly sought after.
Durability: They are generally more durable than Australian opals, but their porous nature requires protection against chemicals and liquids, say Moriartys Gem Art and The Opal Man.