- If you desire that a specific portion of the specimen be analyzed, we suggest that your photograph the item, scan it, or photocopy it, and mark with an arrow the location you want analyzed.
Remember, a single thin section can provide hydration band measurements for two or more facets (e.g., dorsal, ventral, and truncated surfaces).
allow for comparison of the amount of hydration that develops on single source specimens as well as comparison of the amount of hydration developed on several obsidian sources processed simultaneously.
Next, the mineral sample is heated to melting in a vacuum furnace, driving out all the gas.
A variant of the K-Ar method gives better data by making the overall measurement process simpler.
The key is to put the mineral sample in a neutron beam, which converts potassium-39 into argon-39.
Finally, the argon atoms are counted in a mass spectrometer, a machine with its own complexities.
Three argon isotopes are measured: Ar is determined by comparison to it.