Mostly forgotten magic crystals from the past. There are some in the observatory in Bogroot. Used by a cult of Oskahso to sacrifice memories to him.
Your fingers dance over the crystal’s surface like you are watching someone else at work. Intricate arcane symbols appear. - Backstory Codex - Persecuted (RPA-BC)
A woman artisan is trying to remove a Star-Crystal from a glazed tile.
“Once these tiles shone like the stars in the heavens, allowing us to remember their pattern by day,” she says. “You can put coins in the bowl if you want to support my wor—” She freezes when she looks up and sees your face. - Backstory Codex - Persecuted (RPA-BC)
The song of the Dragons is heard on the wind drawing in Culists of Oskahso. They are all holding Star-Crystals.
“But now the Dragons sing again,” says a cultist. “Return and redeem yourself. Fulfill your destiny and raise Oskahso to glory!” They place a crystal in your hand.