Bench terminal

Birthstones by month

The modern list is the one US jewelers have used since 1912, with stones added in 1952 (alexandrite, citrine, tourmaline, zircon), 2002 (tanzanite) and 2016 (spinel); the traditional list is older and overlaps it. Each month's page says what the stone actually is, how hard it is, how it is usually treated, how to clean it and what the listing should say before you buy. We leave meanings and powers to other sites.

JanuaryGarnetDeep red (almandine, pyrope); also green (tsavorite) and orange (spessartine)Mohs 6.5 to 7.5 FebruaryAmethystPurple, pale lilac to deep violetMohs 7 MarchAquamarinePale blue to blue-greenMohs 7.5 to 8 AprilDiamond, Lab-grown diamondColorless; also yellow, brown, pink, blueMohs 10 MayEmerald, Lab-created emeraldGreenMohs 7.5 to 8 (but brittle)JunePearl, Alexandrite, MoonstoneWhite, cream, pink, grey (pearl); green to red (alexandrite); white with blue sheen (moonstone)Mohs 2.5 to 4.5 (pearl); 8.5 (alexandrite); 6 to 6.5 (moonstone)JulyRuby, Lab-created rubyRed to purplish redMohs 9 AugustPeridot, SpinelYellow-green (peridot); red, pink, blue, black (spinel)Mohs 6.5 to 7 (peridot); 8 (spinel)SeptemberSapphire, Lab-created sapphireBlue; also pink, yellow, green, white, 'padparadscha' orange-pinkMohs 9 OctoberOpal, TourmalineWhite, black or crystal with play-of-color (opal); pink, green, watermelon (tourmaline)Mohs 5.5 to 6.5 (opal); 7 to 7.5 (tourmaline)NovemberTopaz, CitrineYellow, orange, blue (treated), colorless (topaz); yellow to orange (citrine)Mohs 8 (topaz); 7 (citrine)DecemberTanzanite, Turquoise, ZirconBlue-violet (tanzanite); sky blue to green (turquoise); blue, colorless, golden (zircon)Mohs 6 to 7 (tanzanite); 5 to 6 (turquoise); 6.5 to 7.5 (zircon)

Natural, lab-grown, simulated

A lab-grown (or "created") stone is the same material as the natural one, made in a lab; a simulant only looks like it (glass, cubic zirconia, a colored look-alike). Both are legal and often sensible for a birthstone piece; the FTC requires the listing to say which. Every month page links the stone's entry in the materials glossary.

Hardness and the ring question

Stones under about 7 on the Mohs scale scratch with ordinary dust and knocks; they suit earrings and pendants better than daily rings. Pearl, opal, turquoise and tanzanite are the soft birthstones; diamond, sapphire, ruby, spinel and topaz are the hard ones. A bezel setting protects a soft stone in a ring.