This large specimen of luxullianite was found in 1965 about 0.5km north of the Museum, forming part of a rockery in front of Carthew House, since demolished to make way for china clay pit development.  In 1965 Carthew House housed the Geological Section of ECLP & Co. Ltd., the leading china clay producer at that time.  Recognising the importance of this specimen, it was taken into the newly constructed John Keay House later in 1965 and resided in the main reception foyer in John Keay House in front of a portrait of Sir John Keay from 1965 to 2002, when it was removed to this Museum.

In the early 19th century the area in and around the St Austell granite yielded some very striking ornamental stones, and luxullianite, from the Luxulyan area (about 5km east of this Museum) was one of the most unusual.  Joseph Treffry, the great Cornish quarrymaster, presented a large piece of luxullianite to be cut and shaped for the sarcophagus of the Duke of Wellington, which can be seen in the crypt of St Paul’s Cathedral, London.  This specimen may have been from the same location as the stone for the Duke of Wellington’s sarcophagus was obtained from.

Queen Victoria and Prince Albert visited Place House at Fowey in 1846 and were so impressed by the newly constructed Porphyry Hall, which incorporated large slabs of polished luxullianite lining the walls, that the Queen exclaimed “That is magnificent”.  Subsequently slabs of Tremore Porphyry and other ornamental granites from the St Austell area were presented to the Queen by Treffry and incorporated into the fabric of Osborne House on the Isle of Wight.  The luxullianite and other stones were cut and polished at “The Porphyry Works”, situated at the Fowey Consols mine site, near St Blazey, which was powered by waterwheels driven by water brought from the Luxulyan area in leats cut into the hillside, which can still be seen.

Luxullianite is principally composed of a black mineral called tourmaline, with prominent large crystals of pink orthoclase feldspar.  Quartz is also present, as well as small quantities of pale green apatite (a phosphate-containing mineral).  Tourmaline contains the element boron and in the final stages of the granite crystallising from molten magma, a fluid rich in boron and silica separated out and chemically changed already crystallised granite to form the spectacular rock we call luxullianite.  Because of the interesting way in which it was formed, luxullianite has been frequently described in student geology textbooks, so many generations of students are familiar with it.  For a long time no in situ occurrence was known but, in recent years, quarrying at Tregarden quarry, close to Luxulyan has revealed a vein of luxullianite.