# Where do mineral veins come from? **URL:** \ **Category:** Factual Questions\ **Created:** [February 7, 2009, 8:59pm UTC](https://boards.straightdope.com/t/where-do-mineral-veins-come-from/484835 "2009-02-07T20:59:52Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [February 7, 2009, 8:59pm UTC](https://boards.straightdope.com/t/where-do-mineral-veins-come-from/484835/1 "2009-02-07T20:59:52Z")
Why do minerals often show up as streaks buried under the ground? The question came to mind because I saw it mentioned somewhere that gold is created naturally only in supernova blasts. I don’t know if that’s true or not (by the way, is it?) but it got me wondering how all the gold ends up congregating together in big chunks and streaks you can find if you dig deep enough. Why the chunks? Why isn’t it simply randomly dissolved (so to speak) throughout the earth? I think I might know the answer, actually, but I wanted to ask because I’m not sure. My guess is it’s because minerals with different densities tend to fall into layers when they’re all melted together, and then as they solidify, they form these “streaks” I’m talking about. Actually, now that I typed it out, I’m pretty sure that’s right. But what the heck, I’ll post this question anyway. -FrL- ---
**Author:** ![Randy\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/r/ee7513/32.png) [@Randy\_Seltzer](https://boards.straightdope.com/u/Randy_Seltzer)\ **Post date:** [February 7, 2009, 9:24pm UTC](https://boards.straightdope.com/t/where-do-mineral-veins-come-from/484835/2 "2009-02-07T21:24:56Z")
Not in most cases, no. They’re usually deposited over thousands or millions of years by water. > **[Vein (geology)](https://en.wikipedia.org/wiki/Vein_(geology))** > > In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved is usually due to hydrothermal circulation. > Veins are classically thought of as being planar fractures in rocks, with the crystal growth occurring normal to the walls of the cavity, and the crystal protruding into open space. This certainly is the method fo... > **[Ore genesis](https://en.wikipedia.org/wiki/Ore_genesis)** > > Various theories of ore genesis explain how the various types of mineral deposits form within Earth's crust. Ore-genesis theories vary depending on the mineral or commodity examined. > Ore-genesis theories generally involve three components: source, transport or conduit, and trap. (This also applies to the petroleum industry: petroleum geologists originated this analysis.) > The biggest deposits form when the source is large, the transport mechanism is efficient, and the trap is active and ready at... ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [February 7, 2009, 10:24pm UTC](https://boards.straightdope.com/t/where-do-mineral-veins-come-from/484835/3 "2009-02-07T22:24:30Z")
> [@Frylock](#): > > I think I might know the answer, actually, but I wanted to ask because I’m not sure. My guess is it’s because minerals with different densities tend to fall into layers when they’re all melted together, and then as they solidify, they form these “streaks” I’m talking about. It’s not because they form layers when they are “melted together,” but rather that they crystallize out of solution under different conditions. Rocks when formed are often not solid, but have cracks or other kinds of channels in them. These can become filled with hot water from volcanic activity in which there are all sorts of dissolved materials, which precipitate out at different temperatures. The ores formed depend on the composition of the fluid and the conditions of cooling. ---
**Author:** ![Absolute](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@Absolute](https://boards.straightdope.com/u/Absolute)\ **Post date:** [February 7, 2009, 10:37pm UTC](https://boards.straightdope.com/t/where-do-mineral-veins-come-from/484835/4 "2009-02-07T22:37:29Z")
Every element heavier than iron was produced in a supernova.