Crystal
A dull grey slab that catches the light and turns peacock — all of it a trick of internal layers.
These are associations the community holds, not settled fact — the more a reading is shared, the bolder it sits.
Turn a piece of labradorite through the light and at one particular angle the grey goes electric — blue, green, sometimes gold, then out again. The effect has its own word, labradorescence, and it is not a colour in the ordinary sense. The feldspar has separated at high temperature into microscopically thin alternating layers, and light bouncing between those layers interferes with itself. The stone is not coloured. It is structured.
It was described in the 1770s from Paul Island off the Labrador coast, which gives it its name and makes it another of the stones with no ancient lore at all. The strongest material comes from Finland, where it is sold as spectrolite. Anything sold as rainbow moonstone is usually a white labradorite rather than true moonstone, which is a related but separate feldspar.
Practice has settled on it as the stone of the threshold and of things only visible from certain angles — transformation, the unglamorous middle of a change, work that is not yet showing. That reading follows so obviously from how the stone behaves that it barely needs a tradition behind it, which may be exactly why it caught on so fast.
Readings practitioners have offered, ordered by how many recognise them. Take what serves, leave the rest.
Carried forward
Common in contemporary practice
Carried through a period of change rather than at its start or end. The stone only flashes from certain angles, and practitioners make a good deal of that — the idea being that some things are only visible from where you happen to be standing.
Carried forward
Common in contemporary practice
Frequently described as a shield against having one's energy drained by other people. This is one of the more modern readings and one of the least traceable; it appears in print from the late twentieth century onwards and nowhere earlier.
Credit what you carry. Much of this comes from living traditions, and some of it from traditions that are closed — held by particular peoples and not offered for general use. Where you know whose practice a reading came from, name them; where you don't, say that too.