Most often it is sold as Caribbean or tropical play sand and is white in color while silica sand has more of a tan color. Yardright, Old Castle, and Southdown are some of the names the aragonite is sold under.
Aragonite is a better buffer, but plenty of people use silica sand without any problems. There is an urban legend that follows the stuff that the silica will cause algae growth but this is more likely linked to poor husbandry. The PH
would have to be that low to dissolve the silica that your livestock would be dead well before you had algae fuel.