Over the past 40 years I have had many samples submitted with the request to find out “what is this stuff”. Today, chemists have an amazing arsenal of analytical equipment that allows a relatively quick and accurate response to that question. In fact, I am reminded of a notable quote from Arthur C. Clarke, “Sufficiently advanced technology is virtually indistinguishable from magic”.
To answer the question “what is this stuff” I have found it helpful to first find the answers to three fundamental questions: (a) what does the stuff look like, (b) what principal elements comprise the stuff, and (c) how are those elements combined to form chemical compounds. To answer question (a) I like to examine the sample using a low power stereomicroscope. Is the sample wet or dry, crystalline or amorphous, single or multiple phases, particulate or fibrous, transparent, translucent, colored, metallic, etc? If the sample is a mixture, it is helpful to separate the major components before proceeding with further analysis. A little time spent doing this physical examination up front will pay great dividends later when interpreting the spectroscopic data.
Next time I’ll address the best ways to answer question (b) “what principal elements comprise the stuff”. Hint: x-rays.