• Hilgardite with Boracite
  • Hilgardite with Boracite
  • Hilgardite with Boracite
  • Hilgardite with Boracite
Sulphates, Nitrates and Borates

Hilgardite with Boracite

$1,200.00   €1,105  £920.00 approx.  

This specimen is priced in US dollars, all other prices are approximate.

ID: CC14072
I have handled many specimens from Boulby mine in North Yorkshire, but this by far is the largest and may be described as either as a large cabinet or museum size specimen. Boulby is a deep polyhalite mining operation which extends out beneath the North Sea, mining both sodium and potassium chloride of Zechstein (middle to late Permian) age. Borates occur above the polyhalite beds and include the minerals Hilgardite (calcium borate) and Boracite (magnesium borate). This amazing specimen comprises of only Boracite and Hilgardite, both as massive and crystalline deposits. Massive Boracite forms the majority of the specimen as a dense and extremely hard yellowish pastel green mass. At one end the Boracite becomes highly vuggy and here forms 1 mm crystalline spheres in their hundreds, of a lustrous greenish yellow buff. The Hilgardite forms large areas of rich salmon pink with an anhedral cryptocrystalline texture. Over some of this is a good coverage of nicely crystallised pale sky blue Boracite. An absolutely super specimen from Boulby!


17.6 × 12.0 × 6.2 cm
Latest Additions, Sulphates, Nitrates and Borates
Boulby Mine, Loftus, North Yorkshire, England, Europe

Minerals on Specimen

Minerals on specimen
Boracite, Hilgardite