Opal, the October birthstone
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Why opal suits October
October's birthstone is opal. What sets it apart from most gems is play-of-color: tiny silica spheres inside the stone split light into color, so the colors shift as the stone moves. No two solid opals show the same pattern.
The Romans called it opalus and prized it highly. The idea that opal is unlucky is much newer. It's usually traced to Walter Scott's 1829 novel Anne of Geierstein, and it hung around far longer than it deserved to.
What the October birthstone means
Opal is traditionally linked with hope, truth and loyalty. Because its colors change with the light, it has also come to stand for faithfulness through change.
October birthstone colors
There isn't just one. Opal can show every color of the spectrum. Green and blue are the most common, orange and gold are less common, and red is the rarest.
The background color of the stone, called body tone, changes the look too. Crystal opal is clear, white opal is milky, boulder opal sits on brown ironstone, and black opal has a dark body that makes the colors stand out.
Opal or tourmaline?
October has a second birthstone, tourmaline. It's a lovely gem, harder than opal and easy to match. If you want two stones that look alike, tourmaline is the better choice. If you want something nobody else has, choose opal: every solid stone is different.
Why solid opal makes the better gift
A lot of the opal jewelry for sale is lab-created opal, or a doublet or triplet: a thin slice of opal glued to a backing. They can look great in photos, but the glue in a doublet or triplet can cloud if the piece is soaked. How to tell if an opal is real shows you what to look for.
A solid opal is one piece of natural stone. It can get wet, it can be worn every day with sensible care, and it can be handed down.
Choosing one
Start with the person rather than the price. White and crystal opal are soft and easy to wear every day. Boulder opal is earthy, and every piece is a different shape. Black opal is the most dramatic and the most expensive.
Every Opalani piece is solid Australian opal and ships with a certificate stating its construction and origin. For a sense of what to spend, see what opal costs, type by type.