Parimatch

A specimen lies face down in front of you. You cannot see what it is — only the clues the card is willing to give up: a hardness band, perhaps a lustre, a streak colour, the way it cleaves, and always the crystal form. From that, you have to name the stone. This app turns mineral identification into the thing it actually is: a process of elimination. The full candidate list sits in front of you, and above it a row of property-filter chips. Tap the hardness band the card reports and everything softer or harder falls away. Add the lustre, and the list narrows again. Rule in a cleavage, rule out a streak, lean on the crystal form — the candidates update live as you go, so you can watch twenty possibilities collapse into three, and then into the one you are prepared to commit to. When you are ready, tap a mineral name. The card flips. You find out whether you read the stone correctly, and you get its Mohs value along with a fact about it — the kind of detail that makes the name stick the next time the same set of clues comes round. A wrong call is just as useful: it shows you exactly which property you leaned on too hard. That is what the specimen case is for. It keeps your streak, records how many attempts each stone has taken you, and — most usefully — works out which property you misjudge most often. If you keep confusing lustres, or keep guessing a hardness band one step too high, the case will tell you so. Over time it stops being a score and starts being a diagnosis of your own eye. The loop is deliberately short. Read the clues, filter, commit, flip, learn. It suits a few minutes between other things as comfortably as a long session, and because the reasoning is all visible on screen, there is nothing to memorise before you start — the filters teach you what the properties mean simply by showing you what they exclude. It is built for anyone who has ever picked up a grey-green pebble and wondered how a geologist would go about naming it: students revising for a mineralogy paper, rock and gem collectors who want to sharpen their field sense, and the merely curious who like a puzzle with a real answer behind it. The stones are real, the properties are the ones used to identify them, and the method is the one you would use with a hand lens and a streak plate — organised here into taps. Narrow the list. Name the stone. Flip the card and see whether you were right.

Emeraldo Flip