Demonstration

When identifying minerals, students often try to take shortcuts by googling photos of the sample or by guessing what they think it is, then assigning the properties of their "solution" to the sample, even if the sample does not exhibit them. For example, they may think something is calcite and claim it reacts to acid, but it is actually halite, which does not react. To address this, I have begun having students use metapuzzles to identify mineral samples. A metapuzzle is a puzzle in which the solutions to a set of clues create a new set of clues that are to be solved. For example, I might give the students talc (A), K-spar (B), pyrite (C), and kyanite (D). From these, they can get a metallic mineral (C) that is very soft (A), with good cleavage (B), dark gray streak (C), that forms blades (D), which they can identify as stibnite. This allows them to concentrate on using observable properties to identify minerals, including ones that you are unlikely to have student samples of.