Looking for a math charm out of the ordinary? This charm is made in the shape of a 45-45-90 triangle, with side lengths 1, 1, and the square root of 2. This charm was designed in the mathematical software Mathematica and can be 3D printed in silver, bronze, or brass to dangle from your charm bracelet. This is an amazing present for an aspiring young mathematician!
For something more classic, consider the pi charm
or the golden ratio charm