The aluminum borate, jeremejevite, is one of the world’s rarest gemstones.

Named after Russian mineralogist Pavel Vladimirovich Jeremejev, the mineral was originally discovered in his homeland's Trans Baikal region in 1883. However, despite the relatively large size of these initial Russian jeremejevite crystals, their lack of color prevented the find from creating any significant waves within the gem trade at the time. This situation changed in 1973, with the discovery of facet-quality, cornflower blue material at Namibia’s coastal Mile 72 campsite, and then further inland within the Erongo Mountains.

While jeremejevite is sufficiently hard for use as a jewelry-set gemstone, the lack of reliable and consistent production means that blue jeremejevite crystals of significant size will likely only be purchased by serious mineral collectors for displaying in their natural form.