Boracite

Boracite, magnesium borate, occurs sporadically in the Permian potash beds in Boulby mine at Loftus near the coastal village of Staithes, North Yorkshire.  Although loved by collectors, it is the scourge of miners as, due to its hardness of 7 to 7.5, quickly dulls drill bits when encountered!  This great specimen shows well crystallised Boracite filling the upper vuggy surface with this grading to massive Boracite, probably more typical of what is usually present in the mine.  Both the massive and crystalline Boracite is a fairly uniform powder sky-blue and the crystals form radiating sprays to around 1 cm across.  A great miniature Boracite from Boulby Potash mine which extends out from the coast beneath the North Sea at a depth of around 1100 metres.