Death of a gold atom? Really? Sorry don't buy that. Atoms don't die though materials in the trans-uranium series do change due to atomic decay. I don't consider that death and while the process can be reversed it requires a lot of effort. Gold does not lose its properties just because its locked into another matrix or chemical bond.
Bit lengthy....
Nitric,
The precipitation of gold from solution is pretty much the same whether its from and aqua regia solution or due to high temperature hydrothermal events. It involves and exchange of ionic carriers that gold can interact with to both allow gold to move into a solution and later be released as a solid.
Probably the most basic way to explain why gold and quartz are so strongly associated was hit apon by 3xfly and EU but not simplified. Both are correct and complement each other. In nature think of plain old water as a universal solvent. Put that solvent under high heat and pressure and it picks up other less solvent materials, ie silicon dioxide *quartz*, more solvent materials like chlorine and sulfur rich materials, ie salts and sulfides, and then interacts with a basically but not totally inert material like gold.
Bear in mind that the solvent has to pass thru a region where both the silica's and gold are present.
Due to the heat and pressure our quartz and gold move into this mobile solvent, water, and along the way push up thru the cracks and crevasses of less reactive rocks. At some point in time the solvent looses the properties, heat and or pressure, to maintain the dissolved materials its carrying. This allows the materials to resume their previous solid state. *just like normal salt does when the water evaporates another reference is to look up super saturated fluids*
Because of the point that these materials return to their solid state and leave the solvent, water, one forms before the other.... silica's will drop out of solution before chlorides or sulfides which carry gold.. and silica's being the most dominate material in the solution form your quartz veins. Now for the gold to drop out of solution one of two things will have to occur. Either the solution now contains other materials that will uncouple the gold from its solution form, other ionic materials, or the material the gold is attached to is so weakly bonded that it naturally drops out of solution. Now the process is not uniform. Some gold will be trapped in the forming quartz, whether in its crystal or in pockets, but most is forced to the boundary layer between the forming quartz and the host rock the solution has pushed up thru... ei the crack.
This boundary layer is what miners look for unless the gold is just all thru the quartz.
Gold in the crack
well if the gold remains with its carrier~ chlorides or sulfides~ then there is little to no free gold in the ore or resulting placer deposits.
If the gold reacts with another material and precipitates out of solution often the gold will form seed crystals and grow just like any crystal. The same would occur if the gold is only weakly bonded to its carrier. Due to other materials in the solution gold generally will not form massive crystals unless its verrrryyy pure.
Gold nuggets. A gold nugget is just a large bit of gold found in a placer deposit. Lots of names describe them but its just a bit of metal. In rare cases crystalline. Gold found in its host rock is considered a specimen but that wont deter someone from removing the host rock on a large bit and calling it a nugget as well.
Thanks for reading. Not looking for total accuracy, just simplification. I do believe the experiments have been performed Cappy.
