Converted

Sky-iron turned into a blade — a thing wholly changed into another use.

Iron Meteorite · The Law of Priority

Family: Iron-nickel meteorite with Widmanstätten pattern
Hardness: 4–5, worked as metal rather than cut as a gem
Colour: Steel grey with an etched crystalline lattice
Signature: Tutankhamun's dagger was forged from meteoric iron

The stone read as the word

The lattice inside an iron meteorite took millions of years to cool and cannot be reproduced on earth. Ancient smiths took that sky-metal and converted it into blades and beads — the object stopped being a rock and became a tool.

To convert is to turn wholly around, con + vertere. This is the stone of a thing that arrived as one substance and left as another.

What it is carried for

Carried when a decision must change what she is used for.
Held at the turn that cannot be walked back.