My phone fell and wont come back on

Yesterday I mistakenly dropped my phone from the top of my stairs to the bottom. The phone was in a silicone case when this happened. When I took up the phone and looked at it, the screen turned a dark grey color, which would not turn off. Today when I went to check my phone Every thing is just black....it wont power on no matter what I try. I would please like to know if my phone is damage beyond repair or whatever.