Circumspect

The stone that filters what comes near — watchful, guarded, nothing careless let through.

Black Tourmaline · The Law of Point

Family: Schorl tourmaline — iron-rich boro-silicate
Hardness: 7–7.5 on the Mohs scale
Colour: Jet black with deep vertical striations
Signature: Polarises light — a slice of it filters what passes through

The stone read as the word

Schorl was used in early polarising instruments because it lets one orientation of light through and stops the rest. It is a mineral that does discrimination as a physical property.

Circumspect means to look around before stepping. This stone is the quiet version of that: not fearful, just filtered — no careless thing gets in.

What it is carried for

Carried when she must be careful about what she agrees to.
Held for a guarded gate on a generous house.