Cutting stone to 2 mm is where most of the cost of this object sits. A thick slab is easy to polish; a thin one deflects under the polishing wheel and is liable to snap, so the yield from a block is low and the ones that survive are the ones you receive.
We use nephrite rather than a more decorative stone because its interlocking fibrous structure tolerates thinness better than quartz or obsidian, both of which would break at this dimension in normal use. It is still not flexible — do not bend it, and do not drop it on tile.
This is a small, quiet object. It is also the least expensive piece of real carved jade we sell, which makes it a reasonable way to see whether you like the material before spending more on a bangle.