Easton's Bible Dictionary
Occurs only in Genesis 2:12, where it designates a product of the land of Havilah; and in Numbers 11:7, where the manna is likened to it in colour. It was probably an aromatic gum like balsam which exuded from a particular tree (Borassus flabelliformis) still found in Arabia, Media, and India. It bears a resemblance in colour to myrrh. Others think the word denotes "pearls," or some precious stone.
Noah Webster's New International Dictionary of the English Language
1. (n.) An unidentified substance mentioned in the Bible (Gen. ii. 12, and Num. xi. 7), variously taken to be a gum, a precious stone, or pearls, or perhaps a kind of amber found in Arabia.
2. (n.) A gum resin of reddish brown color, brought from India, Persia, and Africa.