There's a bug in the Android version with the stock market. Normally, the black areas around the stock market window cover the buttons, but if you have a widescreen android device (like the Galaxy 7+ phones) it doesn't cover the buttons all the way. Thus, when the stock market window is up, you can tap the stock market button again to refresh the prices instantly instead of waiting for the stocks to tick.

This is amazing when you're using 50 gems to remove timers for 10 minutes. You can basically refresh until you get a low enough diamond, buy, refresh again until you get a high value, then sell. This allows you to get 1e20 to 1e25 in multipliers to your money per 50 gems spent, which saves anywhere between 30 - 40 hours of manual stock market grinding. With this method and by spending around 350 gems, I was able to complete my long run of the stock market in around 7 days instead of the 2 months or so it normally would have taken.