Vein (geology) - Wikipedia
Historically, hand-mining of gold ores permitted the miners to pick out the lode quartz or reef quartz, allowing the highest-grade portions of the lodes to be worked,Gems | Minerals | Gold | Quartz | Gem Mining | NC Blue,,Emeralds, rubies, garnets, aquamarines, sapphires, topaz, amethyst, citrine, smoky quartz, rose quartz, moonstone, peridot, and many more varieties of gemstones lure rockhounds and gem collectors from around the world to the Blue Ridge Mountains of North Carolina."Quartz Creek Placer Mines" in Mineral, MT, Gold Placer,,Gold deposits are documented at "Quartz Creek Placer Mines." Gold is present at a grade sufficient to have a strong effect on the economics of an excavation project. It may even be viable as the only commodity mined.