Rock scales are very important for guitar players, they are the foundation of any rock guitar solo embellishing a song by adding flavor and melody. They are the bread and butter of any guitar lesson on the subject.
The pentatonic scale
If there is one type of scale that may be able to bring together all sub genres of rock music, that should be the pentatonic scales. Pentatonic scales are very common in blues songs, which is why they represent an important part for rock music, as well.
These scales are especially used in guitar solos and riffs, which is why they are so common. If you are looking for a way to start learning rock scales, starting with the pentatonic would be the way to go.
The natural minor scale
Blending quite harmoniously with the pentatonic, the natural minor scale is a must learn for any guitar player loving rock music. Even when used alone, this scale has a great effect, as it makes rock songs sound more symphonic. You have probably heard about famous rock symphonies, and you should know that the natural minor scale is heavily used for making these pieces sound the way they do.
The Phrygian scale
If you want to lend a certain flavor to your rock pieces, a good idea would be to try introducing some Phrygian scales into the mix. Used especially for clean passages in rock songs, they give them a certain Spanish inspired flavor that makes them sound quite unique.
The Locrian scale
In case the type of rock music you enjoy playing is darker and more mysterious, you should learn how to play Locrian scales on your guitar. These scales flatten the second and the fifth intervals, making the sounds emitted by your guitar to sound darker, and even downright evil. Depending on the rock subgenre you are into, you can choose between various scales and use them in your songs.
Most common rock scales
If you are just beginning as a guitar player, and rock is your thing, you should start with the most common rock scales. As you may already suspect by now, they are stemmed of blues music, and they deliver certain types of sounds. For instance, you should take into consideration that the minor pentatonic scale is often preferred to the major variation because of its more emotional sound. The use of major pentatonic is allowed, as well, but it is not as common.