Opal

Hydrated silica; precious opal can diffract light into shifting spectral colours. Water content and construction affect care.

Composition: SiO2 · nH2O
Hardness: 5–6.5 on the Mohs scale · scratch resistance, not toughness
Birthstone: October
Care: Clean gently with a soft cloth and mild soapy water; rinse briefly and dry. Avoid heat, chemicals, ultrasonic cleaning and hard impacts. Ask about treatments before cleaning.
Symbolic: Creativity · Crown chakra. Design vocabulary, not a physical effect.

Mineral reference ↗

Pairs well with

Stones that share its meaning.

Amethyst

Quartz · Mohs 7

Calm · Evening ritual · Reflection

Pearl

Organic gem · Mohs 2.5–4.5

Calm · Connection

Moonstone

Feldspar · Mohs 6–6.5

Evening ritual · Reflection

Tourmaline

Tourmaline group · Mohs 7–7.5

Connection · Creativity

Gem properties describe materials. Chakra and intention pairings are symbolic traditions and Mulu design choices, not measured energy or medical effects. Stones are not proven to treat disease or improve sleep.