The coins in Runescape, also known as gold pieces, gold, or just gp, are generally used as currency in the game RuneScape. As any real world currency they can represent the value of almost all other items (unless they can't be traded for gold) or even services in the game. If you look at GP as any other item, they are the by far most traded ones, as players gather them and use for trading for other items.

RuneScape GP appear as small gold coins inside the game that are stackable. In Grim Tales, you can see that the coins actually have a quite sophisticated face but this can never be seen when they appear as tiny coins. Saradomin that the Runescape GP are minted by Fief. There is no explanation as to what the Fief is but since it means a tenure of land subject to obligations of feudal type, it is probably the human kingdoms.

Players can't cast Alchemy spells on RunesScape GP. If a player tries to, a message will be displayed, saying that Coins are already made of gold.... But you can turn other gold items (such as gold ore or gold bars) into coins using alchemy spells.

When you kill a NPC that drops coins and you kill another one in the same spot and it too drops coins the coins stack automatically.

Beside GP, players usually call the RuneScape currency gold pieces, gold, gp, $$$, cash or, most common of all; runescape money or rs money.