Mysterious blue stone

1996/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia

Geologist Anna Grayson has exhibited for the first time in London the “kaleidoscope stone”, found in a small shop in Morocco, on the occasion of Science Week. The surprising feature of this stone is that when analyzed in the microscope with polarized light, it passes from blue to purple and from purple to bright white. These color changes are believed to be due to the “trajectory” of six million fibers of crystal over the rays of light.

However, very little is known about the chemical structure and the origin of this mineral. At least for researchers working at the Natural History Museum in London, it is a headache. Each year there are about forty new samples, but most are very small and many cannot be seen at a glance. The top stone weighs a kilo and a half and can be said to be giant.