Oh, yeah! Now we're cooking Michael.
Very nice job. Working with white on black is a very different way of thinking. And with pastels, no pussy-footing here.
I really like the little 'flecks' of white along the dark right rim of protuding peaks, and the tight little shadows of the two central peaks. It's the little details that make the sketch work really well.
For sharp, fine details using pastel or charcoal (both white and black types) keep a piece of fine sandpaper in your kit. You then rub the edge you want to develop on the sandpaper,
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Those fine rays would have been a tease.