May Birthstone — Emerald, the Spring-Green Beryl
May Birthstone — Emerald, the Spring-Green Beryl
Chromium-coloured beryl, the modern American birthstone for May
The modern birthstone for May is emerald, the chromium-coloured (and sometimes vanadium-coloured) green variety of beryl. The association is part of the standardised American birthstone list adopted in 1912 by the American National Retail Jewelers Association — later the Jewelers of America — and subsequently endorsed by AGTA, GIA, and other industry bodies. Emerald has been associated with rebirth, fertility, and renewal since antiquity, making it a fitting fit for May and the spring season.
The mineralogy in brief
Emerald is the green variety of beryl (Be3Al2Si6O18) coloured by chromium and, in some material, vanadium. The species hardness is 7.5 to 8 on the Mohs scale, which is sufficient for ring use with reasonable care. Refractive index sits in the 1.57-to-1.59 range, with weak-to-moderate pleochroism between green and bluish-green. Most emeralds in the market carry visible inclusions — the so-called jardin — and clarity-enhancement treatments using oils and resins are standard practice in the trade with disclosure.
The 1912 list and its successors
The 1912 birthstone list standardised what had been a varied set of regional and historical traditions, assigning a single principal birthstone to each month for the American retail trade. The May designation as emerald was uncontroversial — historical lists from the medieval and early modern periods had already associated May or the equivalent zodiacal positions with green stones, often emerald specifically. Subsequent revisions to the American list have added alternative birthstones for some months but have left emerald as the primary stone for May.
Notable origins
Colombia is the historical and contemporary benchmark source, with Muzo, Chivor, and Coscuez producing the saturated, slightly bluish-green colour that defines the finest emerald in the trade imagination. Zambian production from the Kafubu area, Brazilian material from Bahia and Minas Gerais, and Ethiopian material from the Shakiso area supply the broader market. Origin reports from GIA, Gübelin, SSEF, and AGL distinguish source on fine stones, with Colombian provenance commanding a clear premium.