Electron Microprobe Analysis
The electron microprobe, used in the sample current-image mode, is useful for study of textural relations of minerals. Contrast in the images produced is due to high-versus-low atomic number. On an electron microprobe equipped with a multichannel analyzer/energy dispersive detector system, mineral grains can be chemically characterized in a few seconds according to their spectra of elements.
The four figures are electron microprobe sample current image photographs of granite in which the heavy minerals magnetite (mt), ilmenorutile (i), zircon (z), monazite (m). thorite (t), and fluocerite (fc) are surrounded by quartz and potassium feldspar (black).
Microprobe sample preparation (polished sections) is relatively time consuming, and analytical work using the micro-probe is relatively complex and expensive. However, in many cases, microprobe analysis provides the only reliable method for obtaining quantitative data on major and minor element composition of minerals or accurate identification of extremely small grains. Photos by G. A. Desborough.