Coasters

Eighteen millimetres is thick for a coaster, and that is the point. A thin disc of stone chips at the edge and slides on the table; a square slab of this thickness sits still under a glass and takes a knock. The edges are eased and the faces are honed, so a wet glass does not stick. The holder's ends rise high enough to hold the pack upright and low enough that the top coaster lifts straight out.

The three stones are the three used across the house: milk white, which is white with faint warm veins; plum, dark purple-brown with pale veins; and the green with brown and gold branching through it. A coaster is the smallest object a stone can become and the one most often held, so each pack is a sample book of the house's marbles, picked up without thinking.

The packs live on a sideboard or a drinks tray, a small stack of stripes until they are needed. The spare length at each end of the holder is what lets the fingers in: eight coasters do not fill it, and what is left is enough for a thumb to tip the first coaster toward the hand.