if you're ready to grow, just germinate them all. I suggest avoiding the white ones, since those are usually undeveloped and so wouldn't sprout anyhow.

The very best marijuana seeds are typically dark, with big dark stripes, and they're fat- like Delta Burke Fat. The fatter the better, and make sure they're not cracked. Just put them all in a wet paper toewl in a dark place for a few days. When they start to split and shoot out white or green sprouts, they're ready to plant. Toss the ones that don't respond after 5 or 6 days, they're usually crap.