No, not all cryptocurrencies can be mined. Some cryptocurrencies, like Bitcoin and Ethereum, use a proof-of-work (PoW) consensus algorithm, which means that new coins are created through a process called mining. In this process, computers solve complex mathematical problems in order to validate transactions and add new blocks to the blockchain. Other cryptocurrencies, such as Ripple and Stellar, use a different type of consensus algorithm called proof-of-stake (PoS), which does not involve mining. Instead, these cryptocurrencies rely on validators, who stake their coins in order to validate transactions and earn a reward. So, it is not possible to mine all cryptocurrencies.