How to clean it
Warm soapy water. Safe in ultrasonic unless fracture-filled — and lead-glass-filled rubies are common, so ask.
Red to purplish red
Ruby
The birthstone for July.
Properties
Composition
Aluminium oxide (Al₂O₃) — corundum coloured by chromium
Hardness (Mohs)
9
Crystal system
Trigonal
Colour
Red to purplish red
Mined in
Myanmar, Mozambique, Thailand, Madagascar, Sri Lanka
Worth knowing
Ruby and sapphire are the same mineral. Red corundum is ruby; every other colour is sapphire.
History
Traded along the Silk Road from Burma; Sanskrit called it ratnaraj, "king of gems".
Practical
Caring for Ruby
How to tell it is real
Almost all commercial ruby is heat-treated, which is normal and disclosed. Synthetic ruby has been made since 1902 and is chemically identical; curved growth lines under magnification give it away.
One general rule covers most mistakes: never store stones loose together. Diamond at 10 on the Mohs scale scratches everything else you own, and it does not need much contact to do it.
What that hardness means in practice
At the top of the Mohs scale. Household dust is largely quartz at hardness 7, which is why softer stones dull over time and this one does not. Safe in a ring worn every day.
Traditional associations
Ruby is traditionally associated with courage, appetite for life and decisive action. In chakra systems it is placed at the Root, Heart, and in elemental correspondence it is assigned to Fire.
These are cultural associations recorded across various traditions, not claims about physical effects. The composition and hardness above are measurable; this paragraph is folklore, and worth reading as such.
Questions
What is Ruby made of?
Aluminium oxide (Al₂O₃) — corundum coloured by chromium, crystallising in the trigonal system.
Which month is Ruby the birthstone for?
July.
Where does Ruby come from?
Myanmar, Mozambique, Thailand, Madagascar, Sri Lanka.
How do I clean Ruby?
Warm soapy water. Safe in ultrasonic unless fracture-filled — and lead-glass-filled rubies are common, so ask.
How can I tell if Ruby is real?
Almost all commercial ruby is heat-treated, which is normal and disclosed. Synthetic ruby has been made since 1902 and is chemically identical; curved growth lines under magnification give it away.
Can I wear it every day?
At 9 on the Mohs scale, yes — it resists everyday scratching.