Any idea / advice on how to test weather something is Aluminum / Silver / Zinc / Gold / Platinum? Etc.
Try finding the weight and mass of the coin and the weights of different metals and play guess and check until you find a match that fits.
I read somewhere that you need a scale, and a cylinder for water to measure the weight and mass of the coin. Sorry I can't remember more but it goes something like that.
Depends on what the "something" is. If the something is a coin it's pretty easy to just look it up and see what it was made out of. Either tell us what you have or post a pic and somebody can tell you.
Its not the coins im concerned with. On my coins I look up the dates and image on it and usually get an answer. However; when metal detecting i sometimes find old silverware (or things such as that) and I cant tell weather or not they are silver.
Well there are different chemical tests you can do, you can Google those. With most silverware and tableware (like platters and dishes) you can look for a hallmark, that will usually identify it for you. Again, you'd have to Google the hallmark. You can some things just by looking at them. Silver reacts differently than base metals in the ground. So the corrosion, if any, can tell a story. Silver won't rust, base metal will. Stuff like that. Your questions would probably be better answered on metal detector forum than here.
Silverware, that is made of sterling silver, are marked Sterling on each individual piece. If there is no mark on them, it's either silver plated, or stainless steel. EDIT TO ADD: The mark could also be 925, which is the purity of sterling silver, as opposed to .999 for pure silver, which the mint uses, and has used, for coins containing silver.
I have a silver service set that has been handed down in my family beginning with my 7th generation grandfather, and it is marked sterling.
Forks, spoons, and knives, it will be marked on the backside of the handle. Trays, bowls(sugar bowls), and pots(tea pots not sauce pots) it will be marked on the underside. The manufacturer's name will also be present on the piece as well, like Revere Silversmiths, or Gorham, etc.
Spoons & forks are usually marked on the back where the handle tapers toward the "business end". Knives are usually marked along the base of the blade where it meets the handle. Chris