PROCESSES
Suppose you have a rock that you suspect may be an ore of some kind. How would you go about determining what might be hidden inside the mixed up minerals? Here is a simple set of sequential processes that can be used to examine your rock.
1. Examine the rock with a hand lens. Describe the crystals and the characteristics of color, shape, and luster.
2. Crush the rock into a sample that can be used for various tests
3. Sieve the sample and separate into different sized particles
4. Use a magnet to see if there is hidden iron.
5. Take a small sample and dissolve any hidden mineral in water. Evaporate the sample and look for crystals.
6. Take a small sample and test with vinegar or other acid. Look for bubbles. Gas production usually means that the mineral is a carbonate, perhaps limestone, chalk, or similar compound.
7. Take a small sample and dissolve it in water. Use electrolysis to see if there is copper, zinc or other metal in the mineral.
8. Take a small sample and float it with oil and soap. See if metal flakes are floated in the sample.
Create a report of findings based upon the tests completed. Based on a comparison chart below, the student can make a hypothesis about the contents of the rock:
Magnetic particles present: IRON in sample
A potion of rock dissolves: The sample has a chloride, sulfate, or other component
It produces bubbles with gas: The sample contains a carbonate
Blue or green dissolved color: Usually means a copper compound
Flakes on the oil surface can be metallic or mica
Crystal structures can indicate certain mineral groups, See sites such as https://www.dakotamatrix.com/mineralpedia
When all examination is completed, a key can be used to help identify the minerals in the rock. See: http://www.mineralogy4kids.org/mineral-identification Once the minerals are predicted, the student should recommend a course of action to mine, separate and process the mineral.
Most rocks that we find are complexes of many minerals. Often, rocks are such a jumble that it is hard to figure out exactly what is going on without extensive separation and testing. Finding a sample that shows some distinctive parts will offer the most satisfying results. Although finding a name for the unknown minerals is sometimes the objective, the journey in determining the attributes of the sample is the focus here. In this sense, whether the correct name is placed on the sample or not is not as important as the value placed on process and the keen observations and reporting.