Birthstone by month

The 1912 list is a commercial standardisation rather than an ancient tradition, and several months were changed for supply reasons. Alternates have since been added. Alexandrite for June, citrine for November, tanzanite for December in 2002 and spinel for August in 2016: mostly to give retailers a wider price range. The traditional lists that predate it vary by culture and rarely agree with each other, which is why almost every published chart differs slightly. Two things about the stones themselves are worth knowing before buying. Four of the twelve are really only two minerals: ruby and sapphire are both corundum, where red is called ruby and every other colour is sapphire, and aquamarine and emerald are both beryl, blue from iron and green from chromium. And the list is not uniformly hard-wearing. Diamond, ruby and sapphire will take daily wear in a ring indefinitely; pearl, turquoise and opal are soft enough to scratch and, in the case of pearl, dissolve slowly in perfume and household cleaners. A December or June stone belongs in a pendant far more comfortably than in a ring.