Crystalline towers grown in a mayo jar

[jasonh300]

When I was a kid, there were this thing I had that involved filling up a mayonnaise jar with water and putting these crystal things in and the crystals would grow into little columns. I think you had to add something to the water to cause the crystals to form or grow, but I have no idea what. They were different colors. Mine never got more than about an inch tall because it was in the garage and one of the neighbor kids knocked it off the dryer and broke it.

Anyone have any idea what this was? And if I can still get it? I think my kids would enjoy it.

[Mr. Blue Sky]

Sugar crystals (http://www.unmuseum.org/excrys.htm)?

[tremorviolet]

Magic Rocks! (http://explore4fun.com/magicrocks.html).

Dunno how they work tho', must be magic... :)

[Q.E.D.]

Magic Rocks (http://explore4fun.com/explorestore/magicrocks.html). I used to love these as a kid. Been around damn near forever, it seems.

[Q.E.D.]

You can also make your own (http://chemistry.about.com/od/growingcrystals/a/aa060704a.htm), if you desire.

[Johanna]

from http://www.waynesthisandthat.com/magicrocks.htm How they work

When one of the rocks (pieces of metallic salt) is dropped into the sodium silicate (an acid) solution, the surface dissolves and combines with the sodium silicate to form a gelatin. This gelatin stops the sodium silicate but allows water through to dissolve more of the rock. This water, now containing dissolved metallic salt, is lighter than the gelatin and surrounding water so it rises, pushing its way through the gelatinous coating. As soon as it comes in contact with the sodium silicate in the water it forms more gelatin, this time on top of the first layer of gelatin. The process continues with water seeping through the gelatin, dissolving more rock, rising, and being gelatinized. Eventually the entire rock is consumed and the process stops. (During the rinsing step, you can look down and often see that the spires have grown in a ring around the rock and that the center of the ring, where the rock was, is completely empty.)

During this process, the gelatin slowly firms up. The spires are then stable and can be rinsed and stored. Prior to this point they are extremely soft and moving the jar can create currents, which bend the spires. After they harden they remain in this bent shape. This can create interesting shapes but they are much more easily broken.

[The Scrivener]

We also made some in a shallow dish with charcoal briquets, ammonia, rock salt, and a dashes of bluing and food coloring, IIRC. This yielded some modest, low-lying crystal growths with a bit of color, but nothing spectacular. (Destructive vibrations disrupting the crystals were a problem, though.) And what with the ammonia, it was really smelly.

[jasonh300]

It was the Magic Rocks. I just ordered a couple of them for the kids.

Thanks for the help!

Jason

[Iggins]

I've wondered if stalactites could be grown with Magic Rocks by gluing the rocks to the lid of a jar. I suppose not, reading the description of how they work.

Maybe growing them upright on a lid in a larger jar, then growing more stalagtites in the smaller jar, with the lid already holding the previous magic rocks...