FMF - Friends of Minerals Forum, discussion and message board

[BeccaA]

I'm brand spanking new, which is why I am asking this.

Aside from Iron Pyrite, can someone please tell me the common and scientific names of everything that can be mistaken for gold in a rock? That way, I can research them all so I can make better judgement as to what I am seeing.

Thank you.

[Tobi]

I think chalcopyrite could be mistaken for gold, its colour looks much more gold-like than pyrite does ...

[Bob Harman]

BECCAA, Other than panning for gold flecks in a stream bed, a major part of your problem will be if you plan on looking for gold, most of what you might find will be tiny flecks in the surrounding host rock.

With that in mind there must be 20 or more lookalikes. Several of the more common ones will be pyrite, chalcopyrite, arsenopyrite, flecks of mica, and even flecks of copper can be mistaken for gold. Some flecks of uncommon and rare minerals also qualify. BOB

[Pierre Joubert]

[BeccaA]

[Pierre Joubert]

Have a look at this site
https://nevada-outback-gems.com/prospect/gold_specimen/Gold_ores.htm
(link normalized by FMF)

Gold rich ore does not always look like gold.

[Pete Modreski]

Becca, let me try to offer a few more comments, elaborating on what the others who replied to you have said. Almost "everything" that one might find that resembles gold is going to be one of the three fairly common minerals that they have mentioned: pyrite, chalcopyrite, or iron-stained mica.

There are two best ways to recognize real gold from any of these other minerals: its deep yellow color, and its softness (malleability). True gold is much more of a deep yellow color than pyrite, which is more silvery-yellow. Chalcopyrite is also a deeper yellow color, but it is likely to have at least some degree of an iridescent tarnish, which can range from bluish to purplish to other colors. Anything that looks tarnished or iridescent, is almost certainly not gold.

The easiest way to test gold for its softness is to press on a grain with the point of a pin or needle, perhaps looking at it with a magnifying glass as you do this. With gold, you can easily impress a "dimple" into the surface of the mineral. Pyrite is much harder; you cannot do this; it is brittle, and you cannot indent the surface, unless you press with so much force that it shatters into fragments, which gold will never do. Mica is soft, but with a needle point, you can tell that it easily splits into flakes, or if you press into the center of a flake, will break and crack around the pinpoint.

Perhaps these extra words will help. I could add, that native gold is REALLY scarce and hard to find, and if you do find any, it is most likely to be just in tiny grains (say, less than 1 millimter in size) embedded in rock. But unless you are able to search at a known gold mine that has been known to produce visible, native gold, you could probably spend a whole lifetime searching and never find any.

Nonetheless, best of luck, Pete Modreski

[SteveB]

That link from Pierre show a good broad range of gold bearing rock examples. Gold is often found in areas where pyrites found.

Collecting interesting rocks is fun and identifying can be tricky. Does the gold still look gold at home under indoor lighting? Most people have compact fluro globes these days or LEDs instead of the older incandescent types. I've notice some of my nicer pyrite crystals look more silver under indoor lighting, but gold still looks like gold.

Get yourself a black or dark bucket and give your specimens a scrub to clean off dirt and clays and dry the rocks thoroughly. Can you see spots of gold floating on the water surface or swirling in the water? This will be tiny flecks of mica. Tip out most of the water then tilt the bucket slightly and vibrate it gently to "pan" the residue, gold and heavy metal grains will settle to the bottom. Gold wont sit on top of the residue, tilt the bucket sideways and as the residue slides sideways you might see gold flecks on the edge grouped together. It will be an obvious gold colour against the dark plastic. Now put the bucket down. If you have gold in the bucket some pieces might be large enough to pick out with tweezers or carefully with fingers to isolate it from other grains, put it in a small contaiiner or bottle for safekeeping. Gold found by panning will be of a consistent colour as it doesnt tarnish. Tip the bucket contents into a container, let the water evaporate before sealing the container. If you're confident you have gold, its now safe in the container so you can learn about panning methods and try to recover it all, which i would do in a large tub as you'll lose some as you pan the waste out of the pan. The you can re-pan what ends up in the tub.

You could also try to map out your finds with a good map and a gps. You can plot precisely where you find interesting rocks. As youget your rocks identified and learn more you might find pyrite is concentrated in one area, chalcopyrite in another and possible gold in a third. By plotting on a map you might see where the quality of specimens changes too and this can tell you where to look for the best specimens.

You should also speak to your local council and library to find out laws regarding fossicking and prospecting and understand the terms and legal standpoints. Speak to your neighbours too if the rocks are on their property too, get their permission to pick rocks if your walks take you on to their land etc. at the least its acourtesy, dont go taking shovels and picks onto other properties without permission. In the library you can find local history information of the regions geology and mining history. You will find maps showing where various minerals and ores are distributed in the region which will give you names of minerals to research and help identify your own rocks. Also rocks you find in your ground will be much the same on neighbouring properties so have a chat with your neighbours, they may have already done the research and can identify your rocks. Even if you find gold odds are you wont make money from it. Abandoned mines were abandoned because the gold was so scarce it wasnt worth the effort to extract. But it can be an enjoyable exercise and you might build up a small amount that is sellable over the months but again check your council on the legalities around this.