Gravity Test ? Need Help With This Very New To Ths

I am assuming you are asking a question about determining the specific density of a coin? If it is a coin that matters, I would only use distilled water to perform the test. Also you will need a beaker that has a milliters measure to the 100ths. Most measuring cups will leaving you guessing. I have used this method for rocks, it will be harder to perform on a small coin. Also if you are trying to use it to test against a counterfeit coin, it could be made of material that is close to the specific gravity of the coin it is proposed to be.

Here's a link to a post I did about specific gravity tests.

The test measures relative values, rather than absolute values. While distilled water is preferred, it is not essential.

I suspect that you are trying to distinguish between a silver clad half dollar (specific gravity 9.53) and CNC half dollar (specific gravity 8.92). The differences are large enough that ordinary tap water would not affect the relative numbers. Running the specific gravity test two or three times and averaging the results should provide enough consistency.

Before going to a specific gravity test, there are other more simple tests that can be applied first:

1. Weight (by itself),
2. Comparative ping tone test,
3. Post pictures here in the CCF, for opinions,
4. Ask a coin dealer.
5. Examine surface metal texture, style, fabric, XRF, check data bases for fakes, specific gravity test. (4. and 5. mainly for ancient coins.)

Isn't that just for 90% Silver ?