The List
| Month | Stone |
|---|---|
| January | Garnet |
| February | Amethyst |
| March | Aquamarine, and traditionally bloodstone |
| April | Diamond |
| May | Emerald |
| June | Pearl, moonstone and alexandrite |
| July | Ruby |
| August | Peridot, spinel and sardonyx |
| September | Sapphire |
| October | Opal and tourmaline |
| November | Topaz and citrine |
| December | Turquoise, zircon and tanzanite |
The two stones added since
Tanzanite was added to December in 2002 by the American Gem Trade Association. It was discovered in Tanzania in 1967 and has been found nowhere else on earth, which makes it the only stone on the list tied to a single place.
Spinel was added to August in 2016, jointly by the American Gem Trade Association and Jewelers of America. For centuries it was mistaken for ruby, including in several famous pieces of royal jewellery, and it has been quietly rehabilitated since.
Which months need a protective setting
Hardness matters the moment a stone goes into a ring worn every day. On the Mohs scale, diamond is 10, sapphire and ruby are 9, topaz is 8, peridot sits around 6.5 to 7, opal around 5.5 to 6.5, turquoise around 5 to 6, and pearl is softer still at roughly 2.5 to 4.5. Emerald is nominally 7.5 to 8 but is so heavily included that it chips more easily than the number suggests.
In practice: April, July and September handle ring life without any special thought. June, October and December need a bezel setting or a protected design if the stone is going on a hand. Pendants and earrings sidestep the problem entirely, because nothing knocks them against a countertop.
Family pieces
A mother's ring with a stone for each child, or a pendant that adds one as the family grows, is one of the most common things we are asked for. It is almost always a custom job rather than a stock piece, for a practical reason: the stones differ in hardness and in size, so setting depth and prong style change from stone to stone along the same band.
If you are planning to add stones later, tell us at the start. Designing the piece to accept them is straightforward. Retrofitting a band that was never meant to grow is not.
