As you traverse the world of Andalucia, slaying mobs and searching through loot chests, you will come across gems (which use the emerald item in-game). These gems are the accepted currency across Andalucia, and can be used to purchase weapons, armour, food, and more.
Gems[]
The currency is available in two forms, gems, and gem notes. Gems are more commonly found as drops from mobs or loot chests, and are stackable up to 64 in number (just as emeralds are in vanilla Minecraft). In order to increase the number of gems you can carry, it is possible to use gem pouches. Gem notes are usually used for trading, and take the form of a piece of paper that is given a value (which can be as large as you want). You do not have to use a gem note of an exact value to purchase an item or a set price (for example you can use a 500G note to purchase a 200G item and will be left with a 300G note), however you can split a gem note by left-clicking with it. You can deposit and withdraw gems in either form.
Banknotes can hold any value
Player Economy[]
Dungeon Realms has a completely dynamic and player-driven economy. Armour and weapons have no set price for either buying or selling, and are instead sold by players through the use of personal shops. Certain items, such as unlevelled pickaxes/fishing rods or HP-replenishing foods are sold by NPC vendors at set prices, however such items are rare and as of such the economy can be hugely variable based on supply and demand.
Banking[]
It's important to note that gems will drop upon death if you have them in your inventory or a storage mule. To that end, it's highly recommended that you deposit your gems within a bank whenever you can. These banks take the form of enderchests, and are found in all major settlements (Cyrennica, Harrison's Field, and Crestguard to name a few). Your bank can hold almost any item in addition to your gems, however capacity for items is limited. On the other hand, you can store an unlimited number of gems in your bank, and they have a dedicated slot within the bank that will remain regardless of whether or not you actually have any gems stored.
Gems can be stacked up to 64 in number
Upgrading[]
When you first access your bank, you will have 9 usable slots (one of which will be reserved for gems). You are able to upgrade the size of your bank by a further 9 slots at a time, however this will cost gems. In order to upgrade your bank size, you must shift and right-click with the required number of gems in your inventory (gems in your bank cannot be used for this). Similarly to shop upgrades, you will be prompted to type in a confirmation code, and each successive upgrade costs more than the last.
Gem Storage[]
The tooltip shown when viewing banked gems
Gems can be stored in the bank by placing them anywhere inside. To check your balance, simply mouse over the gem in the bottom right hand slot of the bank GUI. To withdraw raw gems, left click and type the amount. To withdraw a gem note, right click and type the amount. Gem notes are handy when the amount of gems you want to withdraw exceeds the available space in your inventory.
Collection Bin[]
Your bank also doubles as a collection bin - which is the location that all unsold shop items will be moved to following a shop closure. Shops will close automatically when the server restarts, and can also be closed by the shop's owner. To access your collection bin, simply open up your bank as you usually would - you will be taken straight to the collection bin, from which you can reclaim unsold items. The bank can still be accessed even if there are items in your collection bin, however you need to left-click the enderchest rather than the usual right-click.