Primecoin is a cryptocurrency based on finding prime numbers. Identifying prime numbers plays a central role in cryptography. Primecoin's unique Proof-of-Work (PoW) consensus mechanism is able to increase transaction speeds and improve energy efficiency.
The network searches for special prime number chains known as Cunningham chains and bi-twin chains, which are of interest in mathematical research.

Diamond (DMD) is a Proof-of-Stake coin focused on scarcity. Their marketing materials emphasize the limited circulation of the coin, and the benefits of the network's incentivized cloud mining system, which rewards users for contributing their computing resources.

Nasdacoin is developing a blockchain with a hybrid consensus mechanism that combines elements of Proof-of-Work (PoW) and Proof-of-Stake (PoS). Nasdacoin uses the Scrypt hashing algorithm and is powered by the NSD coin. The company plans on developing a comprehensive ecosystem with a native exchange, wallet, App, and marketplace. They also plan on allowing Nasdacoin holders to transfer their NSD balance to a Visa card that can be used anywhere.