Raiders of the lost dimension

"It all starts with a pigment called Han purple that was used more than 2,000
years ago to color Xi'an terra cotta warriors of the Qian Dynasty. The pigment is known in the scientific world as BaCuSi206 -- and when magnet lab scientists exposed it to very high magnetic fields and very low temperatures, it entered a state of matter that is rarely observed.

The most recent research, published in today's issue of the journal Nature, shows that at the lowest temperature point at which the change of state occurs -- called the Quantum
Critical Pont -- the Han purple pigment actually loses a dimension: it goes from 3D to 2D. "

Note: It's not really the material that is losing a dimention...it's the magnetic field that is constrained to two dimentions when it's cooled to less than a Kelvin and becomes a Bose-Einsein Condensate. Still interesting.