Make new layer and add this brush
Charfade__s_Rock_Brushes_by_charfade
http://charfade.deviantart.com/art/Charfade-s-Rock-Brushes-151024705?qj=4&q=boost%3Apopular+in%3Aresources+tree&qo=988
And give the layer style
Outer glow
Blend mode normal
Color 473e1f
Opacity 100%
Noise 12
Technique softer
Spread 0
Size 29
Contour Linear
Range 50
Jitter 0
Inner glow
Blend mode normal
Color 583a0b
Opacity 100%
Noise 0
Technique softer (edge)
shoke 0
Size 46
Contour Linear
Range 50
Jitter 0
Bevel and emboss
Style inner bevel
Technique smooth
Depth 806
Direction up
Size 35
Soften 0
Angle 120 use global light
Altitude 30
Class contour liner
Highlight mode lighten
Color 585656
Opacity 75%
Shadow mode multiply
Color 552d09
Opacity 75%
Color overlay
Blend mode darken
Color 4e4d49
Opacity 100%

sources used for this step: