March 2025 – Smoky quartz

Our mineral of the month for March is smoky quartz. As the name suggests, this is a grey-brown (‘smoky’) variety of the very common mineral quartz. Smoky quartz forms when quartz is exposed to natural radioactive radiation during or after its growth.

Chemical formula: SiO₂

Location: Galenstock, Uri, Switzerland

Size: 7 x 10 x 10 cm

Weight: 811 g