Identifying "fine" gold
 

I just read an article that said that 20 mesh gold ("fine" gold) is actually black in color (http://www.geocities.com/Athens/Olym...d/physical.htm). Here are the quotations:

"Can you spot gold by it's color? It's usually bright yellow and has a high luster. But fine gold, like other metallic powders, is black; if suspended in clay or some other colloid where the particles are almost molecular size, gold ranges in color from ruby red to purple."

"The size of the pieces is determined with a mesh. Mesh in turn is measured by the number of openings per linear inch. Nuggets won't pass through a 10 mesh screen. Flakes won't pass through a 20 mesh screen. Anything smaller is considered fine gold."

Is this correct?

Re: Identifying "fine" gold
 

Your the guy coming to Colorado to pan right? 20 mesh is huge and believe ME it is gold in color. Even 100 mesh is gold in color just very small. I mine on the Arkansas river here in CO and the gold there is mostly fine. There could be some gold trapped or encrusted in the black sands and they say micron gold is in different colors but I have not seen it. Don't get caught up in trying to catch all the micron gold, just have fun and get a sucker bottle to suck up the little gold ones. Hope you have a great trip. HH Mark

Re: Identifying "fine" gold
 

FYI <SLV> actually lives in Colorado up around Longmont....

Re: Identifying "fine" gold
 

"Nuggets" (also called "course" gold) are colors that are +10 mesh....won't pass thru a 10 mesh screen.

"Medium" colors won't pass thru a 20-mesh screen (said to be -10/+20)
"Fine" colors won't pass thru a 40-mesh screen (said to be -20/+40)...but you don't often see a size 40 screen. 50-mesh is what is usually used.
"Flour" colors (called "dust" in the old days) are anything that will pass through a 40-mesh screen (-40 gold).

All gold in nature is deep mellow yellow. Some is alloyed with other metals like silver that when enough is present makes them a lighter yellow, or copper that when enough is present makes them have a reddish tone.
I've never heard of any other "color" natural gold except what is called "black" gold. These are small colors that look like black sand because over tens to hundres of thousands of years, they have become encrusted with (usually) iron ores & iron oxides. Heating and cracking the coating will usually break the crust free and expose the yellow gold.

Re: Identifying "fine" gold
 

Thanks, goldminer, for the detailed explanation. I had a feeling he was talking about black sands, but he wasn't very clear, nor very accurate it appears.

BTW... Goldhedge is right... I'm already in Colorado. I'm just taking a prospecting trip to a different part of the state this summer.

(sigh)... I wish summer would hurry up and get here. Let's see a sudden warming and heaving flooding!