Recently @RoyTheDragon has put up a time for Flash Mode, utilizing a glitch near the end to complete stage 10 faster.

Normally, in this mode, a magic gem appears every 150 gems you clear. However, if you time clearing your last flashing gem so that it crosses a multiple of 150, you will instead get a magic gem to start the next stage!

And not only that, you then get another one just about 46 gems afterwards instead of the normal 150! I tested and confirmed this with stages 1 and 2, and I even also confirmed that after these two glitched magic gems, they appear every 150 gems cleared as normal (so the next one would be at about 196 total, then 346, 496, etc.)

It does seem like there's a risk to using this: if you miss the mark, you'll have spent the extra time for nothing. It's probably best to use it before the stages where you need a few magic gems to beat them, thus saving you the most time for the risk.