What Is My Birthstone?
August Birthstone: Peridot, Spinel
Peridot, Spinel
August has three recognized birthstones. Peridot, the gem form of olivine, is the classic modern stone with a distinctive lime-to-olive green that comes in only one color. Spinel was added in 2016 and comes in almost every color, with red and hot pink the most valuable. Sardonyx, a banded red-and-white variety of onyx, is the traditional stone.
Peridot forms deep in the Earth's mantle and has even been found in meteorites. Ancient Egyptians mined it on Zabargad Island in the Red Sea and called it the gem of the sun.
Spinel spent centuries being mistaken for ruby; the Black Prince's Ruby in the British Crown Jewels is actually a large red spinel. Its recognition as an August birthstone gave the month a durable, transparent option in warm colors.
August birthstones at a glance
- Modern birthstones: Peridot, Spinel
- Traditional birthstone: Onyx
- Color: lime to olive green (peridot), any color especially red and pink (spinel), banded red and white (sardonyx)
- Traditionally associated with good fortune, strength and clear communication
About Peridot
Peridot is the gem variety of olivine, one of the most common minerals in Earth's mantle. Its distinctive yellow-green color comes from iron.
| Type | Semi-Precious Stones |
|---|---|
| Chemical formula | (Mg,Fe)2SiO4 |
| Mohs hardness | 6.5 |
| Crystal system | orthorhombic |
| Luster | vitreous |
| Streak | White |
| Cleavage | Poor |
- Found in meteorites and on Mars
- Ancient Egyptians called it the 'gem of the sun'
- Cleopatra's 'emeralds' may have actually been peridots
How to tell real Peridot at a glance
- Color: Yellow-Green, Olive Green, Lime Green. Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue.
- Luster: Vitreous. Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner.
- Transparency: Transparent. Hold a thin edge up to a bright light and note whether light passes through.
- Mohs hardness: 6.5. It scratches glass and a steel knife and cannot be scratched by a steel file.
Other stones on this page
Frequently asked questions
What is the birthstone for August?
The modern August birthstone is Peridot, Spinel. The traditional stone is Onyx.
What color is the August birthstone?
Peridot is lime to olive green (peridot), any color especially red and pink (spinel), banded red and white (sardonyx).
Which August birthstone is the most durable?
Spinel (Mohs 8) is the toughest for daily wear. Peridot (6.5–7) is fine for pendants and earrings but can scratch in rings. Sardonyx (6.5–7) is opaque and hard-wearing.
Is peridot the same as olivine?
Yes. Olivine is the rock-forming mineral; peridot is the name used for the gem-quality, transparent green crystals.
