The alchemists saw amber, the golden, coagulated sap, as a potent image for the gold which issued from their growing metallic tree.
Abraham establishes amber as the central alchemical emblem of vegetable gold — the congealed sap of the philosophical tree — linking Crashaw and Milton’s poetic imagery to the opus alchymicum’s production of incorruptible gold.
, A Dictionary of Alchemical Imagery, 1998thesis