So rosemary is generally sold as whole leaves, cracked or ground (powder). If a recipe asks for cracked, I would recommend using standard rosemary available in any supermarket (such as Mrs Rogers Eco Pack), the leaves are quite dry so if you would like smaller particles as a personal preference, they should grind easily in a mortar & pestle or coffee / spice grinder.
I can only assume you have a recipe from Europe or USA? In overseas markets, rosemary is dried whole so it is available in dried needle like leaves around 2cm long. Cracked refers to a method of obtaining shorter particles around 5mm which is the standard here in New Zealand.