Stale Block
A valid mined block that loses a temporary race with another block and is not included in the blockchain’s main history.
A stale block is a real, valid block that was mined according to a network’s rules but did not become part of the main blockchain. This usually happens when two miners find different valid blocks at nearly the same time. For a short period, different parts of the network may see different versions of the chain tip. Once one branch receives the next block and becomes the longer or more-work chain, nodes follow that branch and the losing block becomes stale.
Stale blocks matter because they affect miners, confirmations, and network efficiency. The miner who produced a stale block typically does not receive the block reward or transaction fees, because those rewards only count if the block remains in the accepted chain. For users, stale blocks are one reason transactions are considered safer after multiple confirmations instead of just one. A practical comparison is two people editing copies of the same document at once: the version that gets continued becomes the accepted record, while the other is discarded even if it was originally valid.
Other terms in Mining
Cloud Mining
Renting remote cryptocurrency mining hardware or hash power from a provider instead of running miners yourself.
GPU Mining
Using graphics cards to perform the calculations needed to secure certain proof-of-work blockchains and earn newly issued coins or fees.
Mining Rig
A specialized computer setup used to run mining software and perform the calculations needed to secure proof-of-work blockchains.
Orphan Block
A valid mined block that is not included in the main blockchain because a competing block was accepted by the network first.