Where black sands come from?

[8KCAB]

Found this MDing where I mine placer. Thinking hematite:






Haven't streaked this part of the commode before:






Magnetic enough to hold up a jumbo jet:






Get away from my gold!






Does magnetite and hematite form together?

 

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[Jason in Enid]

Magnatite and hematite are different forms of iron ore and are often found in the same areas. I don't think they form together (as in the same time) but surely in relatively close geologic terms. Both erode out and their similar weights cause them to deposit together.

 

[Lanny in AB]

Magnetite is magnetic. So, if your sample is magnetic, it's not hematite as hematite is non-magnetic (it lacks the necessary oxygen molecule to be magnetic, at least that's what I remember.)

I like your sense of humor with the sample being able to hold up a jumbo jet--nicely done.

All the best,

Lanny

http://www.treasurenet.com/forums/metal-detecting-gold/69-bedrock-gold-mysteries.html

 

[8KCAB]

Magnetite is magnetic. So, if your sample is magnetic, it's not hematite as hematite is non-magnetic

Ah, thanks! I thought maybe hematite, since it streaked brownish sometimes and blackish sometimes, but I guess the brown came from some other minerals in the rock.

 

[smokeythecat]

Black sand normally comes from hell. However, since most people don't believe in hell anymore, it is one of several minerals in minute quantities that erode out of the bedrock and get deposited in the creek bottoms over time. Minerals can include various iron minerals including hematite and magnetite, chromium, and ilmenite and rutile, which are ores of titanium. Columbite and tantalite are other black minerals that occur in black sands also, but you are less likely to find these.

 

[mike(swWash)]

That size of black sand is easy to pan out even for me.