Token

(Fungible) tokens are the currencies of blockchains.

The utility token of the Mosaic Chain is Mosaic Coin (Symbol: MOS).

TIP

On Devnet and Testnet, you can see the term "TMOS" to represent "Test MOS".

Because floating point numbers are inaccurate for financial use cases, blockchains store these values as big integers instead and use these for calculations. Division only happens when the final value is displayed to the user.

On the Mosaic Chain, we use the term tile as the smallest unit that can be represented on the chain.

$$1\text{ MOS}={10}^{18}\text{ tile}$$

Account Balances

Each account has three balance types:

Primitive Balances

Free balance

Tokens that are available for transfers and paying fees.

On Hold Balance (aka. reserved balance)

Tokens locked by the chain for a specific purpose (e.g. staking, governance deposits). Reserved tokens cannot be transferred until they are explicitly released.

Multiple holds are additive: two holds of 0.1 MOS and 0.2 MOS result in a total of 0.3 MOS held.

Frozen balance

Tokens that cannot be transferred. Frozen balance is first sourced from the On Hold balance, and any remainder comes from the free balance.

Multiple freezes are non-additive (maximized): two freezes of 0.1 MOS and 0.2 MOS result in a total of 0.2 MOS frozen.

Derived Balances

We can call "free", "on hold" and "frozen" balances primitives, as they are the building block for other balance types. Those other balance types are called derived balances, because they can be calculated from those primitives.

Total Balance

The full balance of the account, including both free and on hold tokens.

$$\text{Total}=\text{Free}+\text{OnHold}$$

Spendable Balance

The amount that can actually be transferred out of the account right now.

$$\text{Spendable}=\text{Free}-max(\text{Frozen}-\text{OnHold},\text{ExistentialDeposit})$$

Untouchable Balance

The portion of the free balance that is locked and cannot be spent.

$$\text{Untouchable}=\text{Free}-\text{Spendable}$$

INFO

Accounts must maintain a minimum balance called the existential deposit to remain active. If an account's free balance drops below this threshold, the account is reaped (removed from state) and any remaining balance is burned.

Token Supply

MOS has a fixed maximum supply. New MOS is minted as block rewards and distributed to validators and delegators. No inflation beyond the defined reward schedule is possible.

Fees

Every extrinsic requires a fee paid in MOS. Fees are deducted from the sender's free balance before the extrinsic is executed. A portion of the fee may be burned and a portion may go to the block author, depending on the chain's configuration.