Geo

Description
''The currency of Hallownest, made from fossilised shells of various forms. Can be traded for goods or used as toll in various old mechanisms.''

Function
Currency, used to buy goods from merchants or to pay tolls. 3000 Geo is also required to obtain the reward from the fountain in Ancient Basin.

How to Acquire
Found in chests and Geo deposits, and also looted from enemies throughout the game. It can also be acquired by selling items to Relic Seeker Lemm.

Acquiring More Geo
The Gathering Swarm charm allows flies to come and bring dropped Geo to the player. Fragile Greed increases the amount of Geo enemies drop. Together, these items can make farming for Geo far more efficient.

Enemies in endgame areas tend to be the best sources of Geo. Hoppers at the Kingdom's Edge are plentiful and drop significant amounts of Geo, so do Great Hoppers. Many enemies in the Forgotten Crossroads also drop a lot of Geo once the Crossroads become Infected. In the early game, Husk Guards can be useful sources of Geo. Many City of Tears enemies are good sources as well. Great Husk Sentries drop a lot of Geo, though they can be hard to defeat and thus inefficient to farm.

The Grubfather will reward the Knight with significant amounts of Geo for rescuing his Grubs. Relic Seeker Lemm buys otherwise useless items (Wanderer's Journals, Hallownest Seals, King's Idols and Arcane Eggs) for sizable amounts of Geo. This is particularly useful because, unlike your Geo, those items are not stripped from you upon death. If you died twice in quick succession without being able to recover your lost Geo, your relics will still be available for sale. On a Steel Soul run, Rancid Eggs also become sources of Geo, as instead of being used to retrieve your Shade, they're sold to Steel Soul Jinn for Geo.

There are some good one-time sources of Geo as well:
 * In the City of Tears, a hidden enemy known as the Gorgeous Husk can be found in a hidden room not far from King's Station. It drops 420 Geo upon death, even more with Fragile Greed.
 * In Kingdom's Edge, there is a hidden passage accessible by breaking a wall in a room with a Great Hopper and a lot of spike pits. Descending very deep into this passage takes you to the biggest Geo deposit in he game, from which several hundreds of Geo can be acquired.