October Birthstones: Opal, Tourmaline and the Darker Stones of the Season

Choose opal if you love soft, milky color, or tourmaline if you want a bolder crystal, from rose pink rough to glossy black. Opal is the softer of the two, about 5 to 6.5 on the Mohs hardness scale, while tourmaline sits at 7 to 7.5, so tourmaline is the easier pick for jewelry worn every day. For a desk, a pocket or a gift bag, either one is a lovely choice.

Opal is hydrated silica: it holds a little water inside its structure. Precious opal flashes rainbow colors as you turn it, a play of color created as light diffracts through tiny, orderly stacked spheres of silica. Common opal shows no play of color and comes in soft solid shades such as pink, green and cream.

The name likely comes from the Sanskrit upala, meaning precious stone, by way of the Latin opalus. Opal has traditionally been associated with hope and purity.

The pink opal and green opal tumbled stones in our shop are common opal: gentle color, easy to carry, and lovely in a small gift bag.

Opal vs opalite: what's the difference?

You'll see opalite next to opal in a lot of shops, including ours. Opalite is man-made glass, not natural opal. It has a pretty milky blue glow and plenty of people love it, but we'll always tell you which is which.

Tourmaline isn't one stone but a family of minerals, and it comes in more colors than almost any other gem. The name comes from the Sinhalese word toramalli, meaning mixed gems.

Tourmaline can develop a small electric charge as its temperature changes, a property called pyroelectricity. Its knack for attracting ash earned it the old Dutch nickname aschentrekker, or ash drawer.

• Pink tourmaline is traditionally associated with compassion and gentleness. Ours comes as rough crystals still set in their natural rock.
• Black tourmaline is the most common kind of tourmaline and is traditionally associated with protection and grounding. Many people keep a piece by the front door or in a pocket.
• Tourmaline quartz is clear quartz with fine black tourmaline needles grown right through it, two stones in one.

As the nights draw in, we love the look of darker stones, and Halloween is a fun time to give one. Obsidian isn't an October birthstone, but it makes a great seasonal gift alongside black tourmaline.

• Black tourmaline is both an October birthstone and a classic protection stone.
• Obsidian is natural volcanic glass formed when lava cooled rapidly. Mahogany obsidian has red-brown markings, while snowflake obsidian contains pale, radiating clusters of the mineral cristobalite.

For more on black stones, read our guide to black crystals and their meaning.

• For someone new to crystals: a tumbled stone in a small pouch, like pink opal or tourmaline quartz.
• For someone who wears their stones: a black tourmaline pendant or a snowflake obsidian bracelet.
• For a collector: a rough pink or black tourmaline piece.
• Not sure? A Stoneage gift card arrives by email and lets them choose.

You're always welcome to visit one of our stores and choose a stone in person.