Crossword Clue: Black gemstone
Here's the answer to the Black gemstone crossword clue, with an explanation and where it has appeared.
Definition & answer: ONYX
The answer to "Black gemstone" is ONYX. Onyx runs 4 letters — 1 vowel and 3 consonants — opening with O and closing on X. In a grid it fills a 4-square slot whose letters are each shared with a crossing word, so the intersections do a lot of the heavy lifting when the clue itself is tough.
Origin & meaning
Onyx is a banded variety of chalcedony, prized in its glossy black form for jewelry. The rare X ending makes O-N-Y-X a valuable constructor entry.
Common usage
You'll see ONYX in grids regularly — its 4-letter, 1 vowel shape is exactly what setters need to bridge trickier entries. When one intersecting letter is already in place, especially the O or X, ONYX tends to fall fast.
Crossword trivia
Short answers like ONYX are the connective tissue of a crossword. You'll meet ONYX again and again, and recognizing it instantly is one of the quiet skills that separates fast solvers from slow ones.
Stuck on this clue?
The fastest way past a stubborn clue like this one is the grid itself: pencil in the easy crossing answers first, and ONYX will often be the only word that fits the letters you already have.
This clue in different puzzles
The clue "Black gemstone" is just one way to arrive at ONYX. Across different puzzles and editors you may see the same answer clued as "Banded agate variety". Recognizing that a single answer can wear many clues is one of the fastest ways to level up as a solver.
Example sentences
- "Once the O was confirmed by the crossing word, ONYX was the only entry that fit."
- "A 4-letter slot and a clue like 'Black gemstone'? That's ONYX nine times out of ten."
- "I second-guessed it, but the crossing answers confirmed ONYX was right."