Gems are a small item in your Steam inventory that act like a currency inside the trading card system. You cannot buy them in the Steam store, but you can get them from your own items, and you can trade them with other users and bots.
How you get gems
- Turn items into gems. In your inventory, many items such as trading cards, backgrounds and emoticons have a "Turn into Gems" option. Each item gives a small amount of gems, depending on the item.
- Trade for them. Gem bots sell gems in exchange for keys or other items.
Sacks of gems
Loose gems can be packed into a Sack of Gems, which holds 1,000 gems and is a tradable item. Bots usually deal in sacks because they are much easier to move in a single trade offer. You can unpack a sack to get your loose gems back.
What gems are for
The main use is to craft booster packs. For a game that has trading cards, you can spend gems to create a booster pack, which gives you three random cards from that game. The gem cost depends on the game. Booster packs are a way to build full card sets, which is the first step toward crafting badges and raising your Steam level. See how Steam levels work for the maths.
Why bots trade gems
Level up bots make a living by turning one asset into another. A gem bot keeps a stock of gems and quotes a price in keys. A card bot may also quote a price in gems, so you can pay for sets with gems instead of keys. On the directory, the gem bot list shows how many gems you receive per key, and card bots show gem prices per set in their Gems column.