Continuous

One unbroken coat after another over the same centre — never a new pearl, only a larger one.

Pearl · The Law of Perpetuality

Family: Organic gem — nacre laid by a living mollusc
Hardness: 2.5–4 on the Mohs scale
Colour: White to cream with deep orient lustre
Signature: Thousands of nacre layers, each thinner than a wavelength of light

The stone read as the word

A pearl is made one microscopic coat at a time, always over the same centre, and its glow comes from light passing through hundreds of those coats at once. There is no seam anywhere in it.

Continuous means without a gap. This is the last gem of the thirty because it is the one that explains the turn: you do not start a new pearl, you go round again.

What it is carried for

Carried on the day the month begins again over the top of itself.
Held for work with no gap in it.