This toy needs a well educated parent to be of any educational value. The crystal growing bits consist of a flimsy plastic base, a small amount of alum, some food colouring, a 'spider' cut out of blotting paper, two plastic reservoirs and a piece of string. There is also a 'geode', a plastic magnifying lens and three cards with some information on.You dissolve the alum in 70cc of water, and use this to fill pools in the base into which you place the spider and the two chips of rock (plus the food colouring).
In our set, the chips of rock were nonabsorbent and so did not grow crystals at all. Instead, their pool grew small crystals, which we repeatedly scraped out as it dried up, redisolved, and totally failed to get anything to grow on the chips.
The spider collapsed as soon as it was wet, but did eventually grow some crystals, but took a great deal of surreptitious fiddling by parents after bedtime to keep it looking anything like a crouching arachnid.
The string, suspended between two reservoirs filled with salty water, did not drip to form stalactites and stalagmites. It became a very thick crusty, salty piece of string. The surplus water dripped back into the spider pool, making the spider collapse again.
At least we still had the geode. Well, we had a solid chink of quartz, it turned out, not a hollow crystal lined bubble at all.
So this was cheap, and a bit disappointing. "I want another crystal set - a bigger one that works" says our kid.
