boulder opal

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. An [[opal]] consisting of [[concretion]]s and [[fracture]] [[filling]]s in a dark [[siliceous]] [[ironstone]] [[matrix]].

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.