Quartz var. Chalcedony

This rather delightfully structured Chalcedony reminds me of the Devils Tower in Wyoming, made internationally famous in Close Encounters of the Third Kind!  Sitting on a black matrix of what is probably sulphide-included Chalcedony, stalactitic Chalcedony in narrow tubular columns rise vertically, changing from a beautiful lavender duck egg-blue to salmon-flesh-pink.  The Chalcedony also forms small spheres of 1 to 2 mm diameter, which are scattered all over the columns, while adopting the colour of the columns to which they are attached.  A most rare and unusual Chalcedony from one of the famous Chalcedony-rich mines of Cornwall, but whose specific name has gone unrecorded.