Well, let me begin by saying the terms "good" and "evil" are relative. What is good to one person could be evil to another and vice-versa. Also note that magick is not something "of the devil" like Christianity teaches. Satanism is a religion. Note that there are people of other religions that practice magic. Basically, know that the entire "magick is evil" card that the church plays is malarkey. I'd also like to note that in the opinion of some people, Satan is not the evil being that the church implies. I won't go further into that so as to not infringe on beliefs.
Basically, know that magick can be used for good or evil, just like anything else.
It's your choice what you do with it, it doesn't have to be evil for you as other would say it is.. But if you really have to know whether all magic are satanic or not, I would tell you no they are not.. not all of it....It's like wishing for life and for death.. You'd say life is good, death is evil.. On the other side of evil, there is good. Just like there is darkness and light, water and fire, day and night... Yin and Yang.
With Black Magic you can hurt, yet with White Magic you can heal..
It's the way you see it that makes the difference. :)
This is my personal opinion.
If you are a Satanist and doing magick on terms to worship Satan in some way, that is Satanic magick, however, that does not mean that it is "evil" in any way. Don't get me wrong, I don't worship Satan, but (no offense whatsoever to any Christians or Catholics, I am stating what I have found out, if you do take offense, I deeply apologize) In Italian Witchcraft, they believed in a Goddess and a God, and they were named Diana and Lucifer. Lucifer actually means light bringer, he also stands for great courage and rebelliousness, and im talking about standing up for what you believe in, I think that (again, not intended to offend anyone, if in fact, offense is taken to heart, feel free to private message me so I can apologize.) Christians took the concept of Lucifer, and totally twisted it, so people would fear him and not worship him, or practice witchcraft of any kind, even if it wasn't related to Lucifer. If I am erroneous of my information, please correct me, so that I can learn from it.