Because the lava cools quickly, there is no time to create big crystals of Basalt, which means that only small ones that are not visible to the naked eye exist, which means that it has an <span>aphanitic texture.</span>
Some specimens of Basalt are really glassy, most of them are really fine grained and compact. So, they're smooth and slick for the most part, though some of them are a bit rough.