user106667: If I have a bitcoin private key, public key or address, can I know if it is a root private key or some other part which derived from a root private key in an HD wallet by the structure of it?
To be more specific - I don't need to know any details about the parent keys or to connect a hierarchy between two keys - just to know by the structure if to treat this key/address as "unique" one in my program.

user5273: Individual address private keys begin with 5,L or K. What you're calling root private keys are actually called extended private keys and they begin with ?prv where ? is either x,z,y,Y,Z. You can see examples of those here. So that's how you tell the difference.

106667: <p>If I have a bitcoin private key, public key or address, can I know if it is a root private key or some other part which derived from a root private key in an HD wallet by the structure of it?</p>

<p>To be more specific - I don't need to know any details about the parent keys or to connect a hierarchy between two keys - just to know by the structure if to treat this key/address as "unique" one in my program.</p>
 5273: <p>Individual address private keys <a href="https://en.bitcoin.it/wiki/Private_key#Base58_Wallet_Import_format" rel="nofollow noreferrer">begin with 5,L or K</a>. What you're calling root private keys are actually called extended private keys and they begin with ?prv where ? is either x,z,y,Y,Z. You can see examples of those <a href="https://en.bitcoin.it/wiki/BIP_0032#Test_vector_1" rel="nofollow noreferrer">here</a>. So that's how you tell the difference.</p>
