Meet the iMicro Q2p: a polarizing smartphone microscope that fits at the tip of your finger. It has a resolution power of down to 1 micron and 800x magnification. It comes with a focusing stand that gives you easier control. The iMicro Q2p measures only 3.2mm thin, weighing only 0.5g.
You can use this tiny microscope with plenty of smartphones on the market, including those with single or multiple cameras. Expected to ship in April. You can find it on Kickstarter.[where to get it]