If a rock is “really hard,” then it is not a meteorite
Some terrestrial rocks are hard because they contain quartz. Meteorites do not contain quartz. Small stony meteorites can be easily smashed with a hammer. (I have smashed a lot of lunar meteorites with a small hammer.) Quartz-rich terrestrial rocks are hard to saw, but it is not difficult to saw a stony meteorite with a rock saw.
The Braunschweig (Niedersachsen, Germany; L6 chondrite). Meteoritical Bulletin: “Erhard Seemann found a rock impacted into the concrete pavement in his yard 3 m from his front door on the morning of April 23, 2013. …One meteorite of about 1.3 kg broken into hundreds of small fragments after impacting the concrete pavement. The biggest fragment, 214 g, stuck in the concrete making a 7-cm diameter by 3-cm deep depression. Other fragments were <30 g. The gray-white meteorite material is covered by a 0.4-mm thick dull black fusion crust with abundant 50 μm cracks.” Photo credit: Erhard Seemann. More photos: Meteorite Picture of the Day
Unless it is badly rusted, iron meteorites are hard, however. If it is metal and you can bend or break it, then it is probably not a meteorite.
