Base included Size: 11.9x3x2.7 cm Origin: Inner Mongolia, China

Base included Size: 13x7x7.8 cm Origin: Rudny, Kazakhstan

UV reactive with short and long wave Size: 9.5x7.6x5 cm Weight: 360 g Origin: Santa...

Optical calcite with birefringence, as used by Vikings as a compass Size: 3.2 cm

Optical calcite with birefringence, such as that used by Vikings as a compass Size: 3.7...

Optical calcite with birefringence, as used by the Vikings as a compass Size: 4.5 cm...

Size: 5 cm Origin: Inner Mongolia, China

Size: 4.8 cm Origin: Inner Mongolia, China

Size: 4.6 cm Origin: Inner Mongolia, China

Size: 4.1 cm Origin: Inner Mongolia, China

Size: 5.8 cm Origin: Inner Mongolia, China

Size: 6.1 cm Origin: Inner Mongolia, China

Size: 7.3 cm Origin: Inner Mongolia, China

Size: 4.7 cm Origin: Inner Mongolia, China

Size: 5.2 cm Origin: Inner Mongolia, China

Size: 6.2 cm Origin: Inner Mongolia, China

Size: 11.5 cm Origin: Inner Mongolia, China

Size: 11.3 cm Origin: Inner Mongolia, China

Optical calcite with birefringence, as used by Vikings as a compass Size: 4.7 cm

Optical calcite with birefringence, as used by the Vikings as a compass Size: 4.3 cm...

Optical calcite with birefringence, as used by the Vikings as a compass Size: 3.8 cm...

Optical calcite with birefringence, as used by Vikings as a compass Size: 5.6 cm

Optical calcite with birefringence, as used by the Vikings as a compass Size: 5.7 cm...

Optical calcite with birefringence, as used by Vikings as a compass Size: 4.6 cm