Blue John

Jewelry Discussion
1

Hi Andy, For my edification and possibly many others on this
site, could you please explain what "Blue John " is ?

Thanks in advance, Brian ( in Warm 'n Sunny Christchurch
Springtime)

2 
    For my edification and possibly many others on this site,
could you please explain what  "Blue John " is ?

Sorry people. Blue John is a form of Flourite that occurs in only
one or two small mines near the village of Castleton, Derbyshire,
England. It is banded in colours varying from purple through blue
and yellow to clear. The classic material is blue and yellow from
which it gets its name - the imported french cutters called it
‘Bleu et Jeune’ and we corrupted that to Blue John. The tour
guides say the cause of the colouring is still open to debate but
is probably due to bitumen rich fluid percolating through the
host limestone strata. It has been cut into vases and bowls as
well as jewellery for which it is really too soft but is quite
sought after because of its rarity. The tendency to fall apart is
infamous and in the past the rough was dipped or boiled in a tree
resin to hold it together but I now use a 2 pack epoxy despite my
dislike for anything un-natural in a stone. This really is the
only way, as far as I know, to be able to use the material.

Hope this helps and I don’t have an offer for the gold mounts -
in the UK please.

Andy Parker - Ulverston, Cumbria, England