Image imported from derpibooru 
Original Description:
 
Just little sketchdump with small concept :3
 
I think unicorn magic can be different forms.  
For example:  
• Cloudy smoke. Looks like a graceful curly shining cloud. Slightly blurry but still has relatively clear shape  
• Blurry light. Looks like very blurry, not having a clear shape with weak density  
• Flame impulse. Looks like true fire but NOT burns  
• Shiny rings. Looks like…shiny rings :D They fly very quickly from base of horn to its tip and disappear, narrowing to point  
• Flowing smoke. Looks like dense haze that flows from slits of horn. Characteristic for smooth horns with slits along  
• Shining slits. It looks just bright light from slits. Characteristic for horns with a spiral notch  
• Lightnings. Looks like lightning bolts around horn. And one moment: Tempest DOESN’T have that form, her magic just poorly controlled. Lightning form of magic is fully controlled.  
• Shiny hoops. Resembles rings but it doesn’t appear side by side, it looks as one or two hoops sometimes double and / or with rays.
 
Such things. These are not all the forms that I can imagine in unicorns, but relatively basic.  
If anything, you can take this idea for yourself, I don’t mind :3