Crystal Cavern Idle Mine

New: expeditions and core research. A team brings crystals back in two hours, and research makes you a little stronger each day. Plus three small requests daily.

Crystal Cavern is an idle game with no sound at all.

Tap the crystal in the middle of the screen and you earn crystals. That is the whole basic move.

Spend them on buildings and the cave keeps earning every second, even while the app is closed. You can collect up to eight hours of it when you come back.

■ No sound No music, no effects. If you cannot hear, or you are somewhere you cannot make noise, nothing is lost. Haptics are there instead.

■ You choose what reads well Four text sizes. Five colour schemes, two of them maximum contrast — white on black and black on white.

■ Twelve seams As you dig, the seam changes and the crystal shifts colour and shape. You start at Quartz; twelve layers lie below. Each rebirth opens a deeper one.

■ Rebirth Melt everything down into cores. Each core adds +2% to your tap value and income, permanently. The deeper you dig, the more cores are left behind.

■ Glowing orbs Now and then an orb drifts across the screen. Tap it before it fades for a bonus. The best one multiplies everything by five for thirty seconds.

■ Built to be easy to use

• Playable from a keyboard
• Respects the reduce-motion setting
• Progress saves itself on this device
• A save code moves your progress to another device
• Pause whenever you like; nothing accumulates while paused

About adverts: a short video plays only when you claim a bonus. The game is fully playable without watching one. No advert is ever required to progress.

Languages: 17 (English, Japanese, Chinese Simplified and Traditional, Korean, Spanish, French, German, Italian, Portuguese, Dutch, Polish, Russian, Turkish, Vietnamese, Thai, Indonesian), shown automatically in your iPhone's language.