Keep the pen pressed for a few seconds in one spot and let the "Continuous Spray" draw a colorful gem with rainbow prisms and iredescent sheen.
The internal facets are random and have random values to achieve a scintillating effect. The brush is meant to produce varied and unique gems, from which you can then pick the ones you like the most.
Different color combinations can give different results.
Black and white:
Contrasting colors at max saturation, but same luminosity:
Darker main color and lighter sub color:
Lighter main color and darker sub color:
You can paint a texture with it too, of course :)
If you find it difficult to keep the pen in one spot - a ruler or a grid can help a lot.
It's a high-resolution brush, so it may take a moment to load initially or after resetting the brush to default settings.
Increasing the size or using a mouse slows the spray down.