Mineral Detective Game
A mystery mineral sits in each case file, a plain grey lump, and the clues come one at a time: its hardness, its streak, its lustre, its cleavage, a magnet and a drop of dilute acid, the least telling first. Name it as soon as you are sure, because every clue you open costs points. The skill is knowing each mineral's six results well enough to see who is left, and the minerals of each level make a table you can learn as rooms of a memory palace, one mineral to a room.
Clues about a mystery mineral come one at a time, and the sooner you name it, the more it scores. Study each level's field guide first, or go straight to the cases.
How to play
- Pick a level. Before its first case you can study its field guide, every suspect with its six results, or skip straight to case 1. The guide opens again from any case.
- A case opens with one clue. Open the next one whenever you like, up to six. The clue that would settle it comes late.
- Tap a suspect's name to cross it off in your own pencil, or to put it back. It costs nothing, and the game never crosses anyone off for you.
- Press NAME beside a suspect to name it. A wrong name is struck in red ink, and if an open clue had already ruled it out, the game says which.
- After each case the reveal shows all six results, the clue that settled it, and how your pencil did.
With a keyboard, N opens a clue, the arrow keys or 1 to 9 pick a suspect, X crosses it off, Enter names it and G opens the field guide. Escape or Space pauses.
Scoring
A case is worth 600 points with its first clue. Each clue you open after that takes 100 off, and each wrong name 150. A case worth nothing closes unsolved.
A level is five cases, so it scores up to 3,000, with stars at 1,200, 1,800 and 2,400. One star opens the next level. Play a level as often as you like, with new cases every time. Your five best scores for each level are saved in this browser only.
The four levels and the six tests
Level 1, First finds, has quartz, calcite, galena and hematite. Level 2, Metal and glass, adds pyrite, magnetite and fluorite. Level 3, Soft and flaky, adds gypsum, talc and muscovite. Level 4, Top of the scale, adds apatite, orthoclase, topaz, corundum and diamond. Each level keeps the minerals before it, and each adds look-alikes of the ones already in play.
Hardness is on the Mohs scale, from talc at 1 to diamond at 10. The streak is the colour of a mineral's powder on an unglazed tile. Lustre is how its surface takes the light. Cleavage is what it splits into, or none at all. Of the fifteen, only magnetite is pulled hard by a magnet, and only calcite fizzes in a drop of cold dilute hydrochloric acid.
Every result in the game was checked against the Handbook of Mineralogy of the Mineralogical Society of America, and against a second reference. Where a trait varies from one specimen to the next, such as hematite's lustre, the field guide gives each of its usual results. Neither reference gives a streak for topaz or diamond, which are harder than the streak plate, so the game shows white for them, as it does for quartz.
Try our other free memory games.
