Emeralds with highly saturated green color and pure clarity are strongly cherished and coveted by gem dealers and collectors. Those green beauties with the socalled“Gota de aceite”optical phenomenon are rarer. Rarity of such samples causes the scarcity of related research on this subject. This article reports on thegemological features of one 5.1ct emeraldwith distinct“gota de aceite”effect.Also, the possible cause of“gota de aceite”is described and illustrated in crystalline structural perspective.