You should just be able to right-click it and pick it up. See the following image for what it looks like: According to [[w:c:wow:#|WoWWiki]], [[w:c:wow:#|Alterac Granite]] can be found in a [[w:c:wow:#|yeti]] cave in [[w:c:wow:#|Hillsbrad Foothills]] north of [[w:c:wow:#|Southshore]].