The Collaborative International Dictionary
Almagra
Almagra \Al*ma"gra\, n. [Sp. almagra, almagre, fr. Ar. al-maghrah red clay or earth.] A fine, deep red ocher, somewhat purplish, found in Spain. It is the sil atticum of the ancients. Under the name of Indian red it is used for polishing glass and silver.
Wiktionary
almagra
n. A deep red ochre found in Spain; Indian red.