Small-Scale Applications:
Her artwork - it involves a lot of concentration, and a fine application of her ability. From using it to 'carve' stone, or make sandart, pottery, to even something silly like sandcastles! Generally, these applications come through with her touching the type of earth she's changing - all the better to get the fine details on her art.
She can 'throw' rocks and dirt at people or things when she wants - it's not telekinesis by any means of the word. The way that Sparrow manages this, is that she moves the ground fast enough around her in one direction, then halts it quickly, making pieces 'spit/throw' itself at people as it breaks off. Think of how someone might go flying off a bike or car when the brakes are applied without warning. For rocks, she gets them moving and tumbling, and lets them go where they will.
Medium-Scale Applications:
With a little more concentration, she can do things like dig a hole, un/bury something, make repairs in some objects made of earth (cracks in brick, sagging foundation, etc) She can disrupt the earth under someone's feet, making it either soft as in boggy/quicksand or even harden it such an area into something someone can walk on. These applications work better/faster if she's touching the ground, though with a little more concentration on her part, she can manage it without touching. It is one reason that when possible, she does go barefoot, or wears shoes that can be kicked off easily to allow her to touch the ground with her feet if hands are otherwise occupied.
Large-Scale Applications:
She can pull earth out from under a house or building's foundations, leading to a collapse. When upset, her emotions end up channeled into the earth, creating localized 'earthquakes' of various strengths depending on those emotions, and how long her concentration is broken before she pulls it back in again. It is unknown how strong she is in these regards, or how much she could affect faultlines if she was near one. OOC: Anything to do with an earthquake, even a mild tremor, would be passed through Staff before doing. It's not something Sparrow does normally. Only under extreme cases of emotional upheaval.
Other:
While Sparrow can manipulate things like asphalt and concrete, they aren't as easy as something a little more 'natural' in being. Mainly because it takes her a little more concentration to deal with something that has gone through some 'change' as either has. The extremes of making it 'soft' like she can with normal earth, is something that would take her extreme amounts of concentration, and time. It is something that could not be done often - unless she starts practicing it and getting better with it. It's often easier to just undermind the earth /under/ the asphalt and concrete in her mind. For throwing it? Again, a lot of concentration would have to go into this action - because of the changes that both asphalt and concrete has gone through to become what it is. It's not something she's managed to do so far.
Metal:
It's not one of her elements, even if it's in the earth. She can affect the 'earth' that might be around the metal, but for itself, nada. It's one of those misconceptions that some people might have, and one she certainly doesn't dissuade them from thinking.
Concentration:
Her concentration is important to her for her ability, but does manage to keep it, even in the midst of a fight. It's almost second nature to her by now. If, however, she's knocked unconscious or passes out for whatever reason, whatever she was concentrating on, tends to fade/melt at whatever point she had it at. It doesn't return to normal, but neither does it continue towards whatever 'finished' point she was aiming for.
Limits:
Truthfully, she hasn't really tested herself in this regards, ICly. What she's tried to do, has worked for her. But for OOC knowledge, she does have some limits. In 'throwing' earth, she can manage up to perhaps 50lbs of matter or smaller. Size all depends on what she's doing. For her art? She's worked with stone that's several tons, but it's work that took her several weeks to finish for the fine details. In moving earth from under things, she can still manage a few tons of matter, but it then comes down to a matter of range as to how much is being affected.
Range:
Her range is local to her, generally a radius around her. Small scale, is touched, and generally affects within 5-10 feet of her. Medium scale applications can affect up to 40feet from her. The large scale can affect things up to 60 feet from her. The one thing that might affect more, is the earthquake. While localized around her, it could be felt by people in a city block, depending on what level of emotional upheaval that she's dealing with.
