Crystal Mines

How to explore Crystal Mines

Reveal every safe square without opening a cave-in. A number tells you how many of the eight surrounding squares contain cave-ins. Clear areas open together, uncovering small crystals. Mark suspected cave-ins with a flag. You win when every safe square is revealed; flags are helpers, not a separate winning requirement.

Flags, hints and a safe first step

On a phone, switch Flag mode on, then tap to add or remove flags. Switch it off to reveal again. On a computer, right-click a square to flag it. Keyboard players can Tab into the field, use arrow keys to move, and press Enter or Space. The first opening and its neighbors are safe. A daily field begins at the glowing gate so everyone explores exactly the same layout.

Hints mark a safe square without opening it. Undo can take back a flag, a reveal or a cave-in. These friendly helpers are allowed on the leaderboard. Fields are seeded and reproducible, but are not guaranteed to be solvable by deduction alone. If a choice is uncertain, Digby is happy to offer a hint.

Choose your cavern

Easy is an 8 × 8 field with 10 cave-ins. Medium is 12 × 12 with 24, and Hard is 16 × 16 with 48. The daily field is 10 × 10 with 18 and changes at midnight in America/New_York. Choose a size, then New field. Your current field and timer save on this device and can sync through your account.

Digby’s advice

Start beside a clear patch. If a clue already touches the right number of flags, its other neighbors can be explored—provided your flags are correct. If all of its remaining covered neighbors are needed to satisfy the clue, those squares can be flagged. Take your time; there is always another bright discovery.

A friendly daily race

Use Start ranked run below to enter today’s board. The server supplies the seed and checks every reveal and flag before accepting a completed field. Daily runs use the shared glowing gate; fresh ranked runs use Easy size. The server clock includes pauses and network time.