Examples of cast aluminum would be gas grill covers, hard drive cases, some disk drive frames. If you get a second take a hammer to one and get a feel for it.
That is exactly the problem. I got two hard drive cases and I am pretty sure one is aluminum and one is zinc, but I am not 100% sure which is which. I whacked them a big hammer and one bent and one broke. I will try to post some pictures later..
I took a 5 lb sledge hammer to these three things. The old faucet looking thing broke, while the other two withstood around 5 heavy hits from the sledge. I take it that the faucet is ZN and the other two are aluminum??
Those who trade liberty for security have neither.