Bottles of gold dust hidden under the floorboards in old houses have been in the news. How can gold dust be identified by an amateur? There is help online. Search for "gold dust images" using Google Images or Bing. There are hundreds of pictures of all types of gold: nuggets, flakes, dust, etc. Does the bottled dust rehabbers found look like something in the pictures? Is it the right color?
Home testing for gold requires nitric acid and hydrochloric acid. Commercial testing kits also use the acids. A kit will have the needed bottles and instructions. But testing with acid is dangerous. Warning: If you try this, when you're diluting the acid be sure to pour the acid into the water, not the water into the acid.
If a test shows the dust is partially gold, it must then by assayed to determine how much is gold and how much is dirt or other material. Perhaps the safest, best way is to take the bottled dust to a local buyer of gold. Every city has ads for local shops, usually jewelers, offering to buy gold. The shop may have a mass spectrometer that tests samples. Ask if there is a charge. Let the shop test, assay, and determine fineness. Published gold prices are for 24 karat down to 10 karat gold. The dollar value is determined by how pure the dust is--what percentage of the dust is gold--and, of course, the weight.
Kovels.com has a gold calculator to help you find values. Click on Kovels.com, go to "Resources" at the top of our home page, then click on "Gold Calculator." Fill in the blanks to calculate dollar value.
See Kovels Komments, Jan. 18, 2012, for information about selling gold jewelry.