Pearl
Organic gem
Take care.
- Sensitive to heat: Keep it away from heat and sudden changes of temperature, including hot lights and ultrasonic cleaners.
About it
Gem grown in layers of nacre by oysters and mussels. Real pearls feel gritty when rubbed gently against a tooth, while imitations feel smooth; nearly all on sale are cultured. Acids, perfume, and heat dull them.
- Type
- Organic gem
- Group
- Mollusc pearl (nacre)
- Hardness (Mohs)
- 2.5–4.5
- Specific gravity
- 2.6–2.85
- Lustre
- pearly
- Colours
- white, cream, pink, silver, gold, grey, black
- Transparency
- opaque, translucent
- Cleavage and fracture
- none; uneven fracture
- Under UV light
- often bluish white or cream under longwave UV
Typical values: real specimens vary. For more, see mindat.org.