Eduard Josef Gübelin (1913 – 2005) was a German gemstone researcher. studies on gemstone inclusions laid the groundwork for the microscopic identification of gemstones. Gübelin's used poetry to validate gemstones, as noted in the book Emeralds A Passionate Guide. Gubelin was one of the first gemologists to recognise the butterfly wing effect in Colombian emeralds. He also founded Gübelin Gem Lab.