> I was curious why the dye was blue instead of the Tyrean purple we are familiar with.<

Actually, we do not generally know whether ancient "blue", "purple", etc. was blue or purple or what.  The purple dye produced by various mollusks, especially muricids, will give a range of colors, from blues to purples, depending on how long things are dyed, dye concentration, etc.

>Guess archaeologists do not worry about verifying their material when it comes to shells.<

When it comes to publishing on their finds, they also seem fond of figuring the shells that are extensively carved, rather than more identifiable specimens.  Of course, they also may be confused by the changing names applied to species.

    Dr. David Campbell
    Old Seashells
    University of Alabama
    Biodiversity & Systematics
    Dept. Biological Sciences
    Box 870345
    Tuscaloosa, AL  35487-0345 USA
    [log in to unmask]

That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa