A Mosaic tablet is a flat slab or plaque, suitable for enscription or engraving. Tradition makes this the form of the tablets on which Moses brought the Ten Commandments down from Sinai, hence the name. Though found in period art, we have no examples of them from period armory. In Society armory, Mosaic tablets are usually shown in conjoined pairs, though the fact is always blazoned. See also book.
Collawyn Lughaidh O Cearbhaill bears: Per fess argent and gules, in pale a lion contourny maintaining an Irish harp and two Mosaic tablets conjoined in fess counterchanged.