In what geological situations can I find gold?

Question

I've heard that gold ore is often associated with quartz veins. What geological processes enable gold particles to naturally cluster together like this? What characteristics/properties should I look out for on the surface of a rock that are likely to yield gold within it? Are there remote sensors that I use to detect the presence of gold in a rock?

Answer 1

I've heard that gold ore is often associated with quartz veins. What geological processes enable gold particles to naturally cluster together like this?

Gold particles are often embedded with quartz in a rock. Native gold also occurs as larger grains, eroded from rocks, that are found in alluvial deposits. The latter size of gold is richer at the surface of gold-bearing veins due to mineral oxidation and weathering, as well as washing of dust into waterways, where it is formed into gold nuggets.

What characteristics/properties should I look out for on the surface of a rock that are likely to yield gold within it?

Gold exists in ores of rocks that are Precambrian and younger, usually as a gold-silver alloy with 90-92% gold. If silver exceeds 20% of the solution, the color will be silvery to golden-silvery. Native gold exists as microscopic to very small particles of gold within ancient rocks. Mixtures of native gold and sulfide minerals often form lode deposits.

Are there remote sensors that I use to detect the presence of gold in a rock?

Remote sensing can be used as a technique for detecting gold in the earth's crust, and its application can outline exploration targets and map hydrothermal alteration. Although gold is invisible to remote sensors themselves, it can be located indirectly by the presence of minerals that form with gold, based on their spectral data.