Detailed information
Species
Bournonite, Quartz
Dimensions
32 x 55 x 41
mm
Weight
93 g
Locality
Herodsfoot Mine Lanreath, Liskeard District Cornwall, England
Condition
No recorded repairs
This dramatic 'cogwheel' Bournonite is from the all-time classic occurrence at Herodsfoot mine in Cornwall. It is not the Type Locality - that is Wheal Boys elsewhere in Cornwall - but it was, for over a century, the world's premier locality for crystallized Bournonite and remains the most sought after occurrence for specimens. This large miniature specimen from Herodsfoot mine is an absolute cracker, featuring an incredibly large cog-wheel Bournonite crystal on matrix. At over 4 cm across, the main crystal is an iconic 'cogwheel' with beautiful gunmetal colour and patina. The Bournonite crystal sits upright on a thin bed of crystallized Quartz on killas rock matrix and is completely exposed for display on one side. On the other side the crystal is mostly coated with coarse white Quartz crystals which also partially coat several other bladed Bournonite crystals. Virtually all of these specimens were extracted whilst the mine was operational during a narrow window in time during the 1860s. For those wanting to know more, I thoroughly recommend the Herodsfoot mine article written by Roy Starkey and published in The Mineralogical Record in 2012 (Vol. 43, No. 4). For size, the main Bournonite crystal here is exceptional, and in fantastic condition. Ex Malcolm Southwood collection.
