SPINEL
Spinel
Spinel
A distinct mineral whose red stones were sometimes confused with ruby in history. Blue, gray and many other colors are also found.
GEM PROFILE
Basic properties
- Mineral or material
- Spinel
- Main chemical composition
- MgAl₂O₄
- Crystal & structure
- Cubic (isometric)
Octahedral crystals are characteristic. Spinel is normally singly refractive.
- Typical colors
- Red, pink, purple, blue, gray and more
- Mohs hardness
- 8
A measure of scratch resistance, distinct from resistance to impact or breakage.
About hardness and durability - Representative sources
Examples of known sources. Determining the origin of an individual stone requires examination and comparison with reference material.
- Common cutting styles
- Faceted cushions, ovals, rounds and other shapes.
Explore cutting styles
LOOK A LITTLE CLOSER
What to observe
Even when similar in color to ruby, spinel differs in crystal structure and optical properties. Color alone cannot identify the mineral.
TREATMENT & CARE
Treatments & care
Treatments & identification
Heating and fracture filling may occasionally be encountered. Synthetic spinel also circulates in the market.
Everyday care
Lukewarm water and mild detergent are the basic choice. Avoid ultrasonic or steam cleaning for fractured or treated material.
Cleaning depends on treatment, inclusions and mounting. If a stone's condition is unknown, ask your jeweler or a gem specialist before cleaning.
READING & REFERENCES
References
Public sources for learning about this gemstone's general properties.
- GIA · Gemological reference
- GIA · Care & Cleaning
- GIA · Gem sources and fundamentals
- GIA · Gemological reference
This dictionary provides general educational information. Values are representative and do not identify or grade an individual stone. Locality examples include historical deposits.
Sources checked: October 19, 2026