There are three major elements in this illustration: the customary half-image of Maria Orans; King Solomon pointing with his scepter to the Marian medallion, and the "Tower of Ivory" which seems to be part of a castle.
Solomon seems to be uttering these words, "Your neck is like a tower of ivory" (Canticle of Canticles 7:5). This sentence is part of the description of Shulammite's, the bride's beauty. Attributed to Mary in the Middle Ages, this symbol highlights Mary's eminent spiritual grandeur, beauty and fortitude (J. H. Newman).
The reference to Solomon includes ivory as the material from which he built his home, "The king also had a large ivory throne made, and overlaid it with fine gold" (1 Kings 10:18).