In GeoMag and SuperMag, incredibly strong bar magnets, clad in plastic, hold tightly to non-rusting steel balls to build geometric figures, bridges, skyscrapers, etc.


Kathleen Gajewski built and photographed these models. (Click on the pictures to see larger images.) The green arch is SuperMag, and the yellow tetrahedron and green stellated icosahedron are the original GeoMag - both manufactured in Italy by Plastwood. The difference is that Geomag's bars were all the same length (ideal for Platonic solids), while SuperMag has a shorter length, as well, the right length for diagonal pieces within rectangles. Geomag does not make strong models of molecules, because the bars can rotate on a ball. A sturdy construction will always be made of triangles, since the lengths of the sides of a triangle determine its angles, unlike those of rectangles.



The mass of the pieces is impressive, giving the pieces a satisfying feel. If you don't have to worry about a small child applying it to a CRT monitor (magnets are bad for television tubes), or to your credit cards, it makes an ideal adult desk toy. Be especially careful to keep it out of reach of toddlers when there are GameBoy games, GameCube memory cards, videotapes, or anything else that stores information magnetically. The magnets do not have to actually contact the media to erase their contents.

I once added some locally-purchased steel balls to my set. In our high humidity, the plating wore through quickly, and the non-Plastwood balls rusted quickly. The balls supplied with the GeoMag and SuperMag sets are highly resistant to rust, in a humid city. These things are made with quality.

I purchased my first set of GeoMag at The Construction Site , a great toy store for finding cool building toys, and later in a local chain toy store, the late Zany Brainy. It's also one of the few good math toys that can be purchased from Amazon - if you purchase from them after clicking on the picture link to the right, I'll get a small kickback which will help support this web site. There are many places to buy it, though. If your locally-owned toy store has what you need, help them stay in business by buying from them.

Other toys that are very similar to GeoMag include Roger's Connection, with four-inch rods instead of one-inch rods, and Mags, whose rods are thin in the middle and thicker at both ends. Plastwood claims that GeoMag contains stronger magnets than any of its competitors; however, I do not know how significant the difference may be. Don't get the competing brand Magnetix, which is made in China, because the magnets come out sometimes and can be deadly when swallowed. (See the Magnetix recall notice at the CSPC.) Geomag is made in Switzerland and certified free of phalates and other questionable chemicals.

[Updated July 29, 2008]