Hi Avril, I recently did a fair amount of online research on royal (Tyrian) purple dye, while preparing an article for American Conchologist. I did not come across any place that offers the dye itself for sale. This is no great surprise, given the difficulty of producing it, and the consequent high price, compared to comparable modern synthetic dyes which are far easier to manufacture and much cheaper. However, I did come across a little book that supposedly gives recipes for preparation of the dye. Perhaps your inquirer would find it interesting. It's called Tyrian or Imperial Purple Dye, and can be found here, if anyone is interested: http://www.georgeweil.co.uk/pdf/21_natural_dyeing_books.pdf He/she might also find this interesting - a bibliography to literature on Tyrian Purple: http://www.chriscooksey.demon.co.uk/tyrian/cjcbiblio.html Regards, Paul M.