Hi James,
To check if your “Gutter collection” contains possible meteorites you can try following tests:
1. Native Iron test: a magnet is attracted. This test was apparently positive.
2. Streak test: Therefore you scratch the rough side of ceramic material ( such as an old bathroom tile). If negative, this means if no streak (colored or not) is visible, it is a vote for a meteorite.
3. DMG test or Nickel test. This can be done qualitatively bij etching a part of the material with an acid solution (Nitric acid or Hydrochloric acid 1% solution in water). Afterwards you rub the stone with a solution containing 1% DMG (Dimethylglyoxime) in alcohol with 10% ammoniumhydroxide. (available at local pharmacies or on line shops). If positive means a red color is appearing. You may then go to a specified lab to do a quantitative test to determine the % Nickel.
4. Estimate the density of the rock: first weigh it on an analytical balance (ask local pharmacist), then put it in a measuring cilinder filled with water, put the rock in it and calculate the difference of the water level. Calculate density which is mass divided by volume. Depending on the type of meteorite this gives 3.5 to 4.5.
If all tests are positive go to a university lab for detailed analysis!
Success,
Kind regards,
Marc.