trial_description_8:
The shell of a large bivalve (according to D.S. Reese, 26 January 1984, is a marine Clycymeris), used as palette.
In the bottom, a pool of dull red paint; on the edge the marks of paint where the painter wiped his brush. Sampled by R. J. Gettens 7/21/71
Coloring matter identified by E. Caley as cinnabar: native mercury sulfide (4 April 1937).
ADDENDA Coloring matter identified by S.W. Midgley as Cinnabar, Natural Mercuric Sulfide.