A vintage bracelet constructed from sterling silver and nine oval panels of Blue John stone. It has a dog clip style fastener and bears a full English hallmark on the side, but too small for me to read. I believe this dates from the 1980's. It has not been cleaned. It measures approx. 7 3/4" x 7/16" and weighs 20.8g.
A similar one, on sale today at the Blue John Mines retails for approx. $490
Blue John (also known as Derbyshire Spar) is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale