Magic-Numbered D30 - The world's first numerically-balanced 30-sided dice!
In order for dice to be as fair as possible, physical and numerical balancing are both important. That's the case with these OptiDice D30 dice from The Dice Lab. Read below for more detailed information.

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Additional Information from the manufacturer on these Numerically-Balanced D30 Dice
Physical balancing of dice requires use of isohedral polyhedra. The polyhedra traditionally used for the d20 and d30 are such polyhedra. Perfect physical balancing is still not possible, though, due to physical differences in numbers, small inaccuracies in molds, additional inaccuracies introduced during tumbling, and density variations due to defects like voids. In addition, it's possible to affect the roll of dice to a degree by carefully controlling the manner in which they're tossed. For these reasons, dice are more fair if they are numerically-balanced as well. For example, a void inside a die near a vertex (a point where three or more faces come together) will cause that vertex to preferentially face up when the die is tossed. The effect of such defects can be minimized by arranging the numbers such that the sum of the faces meeting at each vertex is the same.

A d30 has 32 vertices, of two types; 20 where three faces meet and 12 where five faces meet. Since the average face value is 15.5, an ideal numerical balancing would have ten vertices summing to 46, ten summing to 47, six summing to 77, and six summing to 78. We found a dozen ideal numberings based on these criteria. For the d30, ideal face sums are not possible. The numberings of The Dice Lab's d30 were worked out by Bob Bosch, a Professor of Mathematics at Oberlin College. Die measures measures 27mm face-to-face.

WARNING: CHOKING HAZARD - Small parts. Not for children under 3 years.