How Ruby and Spinel differ in what they are, color, hardness and care.
| Ruby | Spinel | |
|---|---|---|
| What it is | The red variety of the mineral corundum, colored by chromium. One of the most durable gems. | A hard, durable gem that is often mistaken for ruby or pink sapphire. Added as an August birthstone in 2016. |
| Birthstone for | July | August |
| Colors | Vivid, pure red is most important; "Pigeon's blood" red with blue undertones is the most prized; Thai rubies are often darker with brownish undertones | Vivid red; Cobalt blue; Bright pink; Bright orange; Violet; Purple; Green; Brown; Gray; Black |
| Mohs hardness | 9 | 8 |
| Toughness | Excellent, with no cleavage; a good choice for rings worn every day. | Good, which makes it a durable choice for jewelry. |
| Everyday wear | Great for everyday rings | Good for everyday wear |
| Ultrasonic cleaner | Usually safe for untreated, heated and lattice diffusion treated stones; not for filled or dyed stones | Usually safe (fractures can be a problem) |
| Main sources | Myanmar (Burma), Mozambique, Thailand | Myanmar (Burma), Sri Lanka, Tajikistan, Vietnam |
| Common treatments | Untreated and heat treated rubies are very durable. Fracture filled stones (usually with high lead glass) need more care. | Some spinel is heat treated (stable). Fracture filling is rare. |
Ruby is the harder of the two (9 on the Mohs scale). Choose by the color you love and how the piece will be worn; for a ring worn every day, the tougher stone will last better.
Sources: GIA: Ruby care and cleaning, AGS: July birthstone, GIA: Spinel care and cleaning, AGS: Spinel. Checked October 16, 2026.
Birthstone of the month
On the first of each month: that month's birthstone, what it means and how to care for it.
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