How to Identify Rocks that Contain Gold?

Gold occurs naturally but in the form of tiny particles and is often mixed with other minerals. Therefore, searching for old is a very complex mission unless you know where to look. For instance, gold shows its presence in an area by means of various signs. Hence, in this article, I will explain everything that you need to know before setting out on your adventure to find rocks that contain gold.

When hunting for gold, gold-bearing rock identification is the critical element. It is because goldrush is very tiresome, and you may end up looking in the wrong place. As a matter of fact, expert gold prospectors prefer to look for rocks and minerals that are known to contain gold rather than directly looking for gold.

Rocks and Minerals Linked with Gold

There are millions of mineral combinations found on earth. However, only a handful of them are known to truly contain gold and not fool’s gold. That’s why Shakespeare said, “ All that glitters is not gold”. Therefore, when hunting for gold, you really need to keep an eye out for these minerals:

Different Rocks that contain Gold
Different Rocks that contain gold
  • Quartz: Gold and quartz combine naturally, and that is why gold is often found in quartz rock. Moreover, the pure white color of quartz makes it easier to spot anything mixed in it. The gold in quartz rock value is also similar to that of gold ore. Therefore, when in a gold-bearing area, it is best to first look for quartz.
  • Magnesium Ferric: Experts usually link gold with heavy-mafic or Magnesium Ferric. It is because gold is often found next to this dark-colored mineral. The best way to identify heavy-mafic is to look for a rock that is dark colored and has black or red traces on it.
  • Malachite/Azurite: Your second-best chance of finding gold depends on the azurite stone. It is a semi-precious stone often found in green color. Therefore, if you find such stone near the gold site, it would be best to pinpoint your searching radius near it.
  • Alluvium: Alluvium is a black-colored deposit often found in the creeks and riverbeds. The alluvium is generally a mixture of eroded particles of gold and other materials washed away by the running water. If you find alluvium near the riverbed, take out your pan because you just found the gold.
  • Chalcopyrite: Chalcopyrite is also known as fool’s gold because its appearance and weight are similar to real gold. However, this gold-looking rock is a combination of copper, iron, and sulfur (Cu-Fe-S). As a matter of fact, many gold miners are often fooled into thinking that the chalcopyrite is real gold. But the good news is that fool’s gold usually leads to real gold. Therefore, if you happen to find chalcopyrite on the river bed, search carefully because real gold may be nearby.

How to Plan your Search and Extraction of Gold?

Gold is found in abundance in nature and can be found anywhere in the world. The problem is that 90% of the gold is either found in tiny particles or attached to some other mineral to form rock with gold flakes. Therefore, it is beneficial to plan your search and mode of extraction before going out in the field. For instance, the method of gold extraction from alluvium is different from quartz rock gold extraction.

For the most part, you will be searching near streams, rivers, and other running water bodies. The best way to identify raw gold is to look in the creeks and riverbeds. Also, carry with you a metal detector along with ore extraction and panning tools. Finally, don’t only look for gold but also look for traces of gold using mineral rocks such as gold in granite or alluvium.

What is Placer Gold?

Placer gold
Placer Gold

Placer gold or natural nuggets are large gold deposits often found in dry streambeds or riverbeds. These nuggets are usually found many miles away from their place of origin. Therefore, finding placer gold does not necessarily mean that you just found the gold mine. 

You can find placer gold by using a metal detector and panning techniques. The metal detector helps to identify the location of the placer gold in the dry creek bed. However, sometimes the gold nugget is of small size and mixed with dry soil or sand. Therefore, you can try the panning method to extract gold from the mixture.

Moreover, you should know that the panning technique is the same globally. For instance, gold panning in Arizona is the same method as used for gold panning in Colorado.

Gold Identification Tests

Imagine you are gold hunting on a riverbed, and suddenly your detector beeps. You dig the pinpointed spot and find a large gold nugget. However, don’t go backflipping just yet because your find may easily just be fool’s gold or iron pyrite. Therefore, you need to perform various tests on the rock to tell if a rock has gold in it. Here are some of the ways of how to identify gold ore on the site:

Crush the Rock:

Rock crushing is the oldest and the most basic method of testing a rock containing gold. As a matter of fact, the miners first used this method in the 1840s when mining for gold in Mexico. However, this method includes crushing your found rock into smaller pieces. Therefore, only use the crush the rock method if you don’t have access to other equipment:

  1. Take a heavy mallet and pulverize the rock by crushing it into smaller pieces.
  2. Place the dust on a sluice box and slowly pour water to push the material slowly down the angled slide.
  3. Gold is heavier than other material, so it gets stuck in the ridges while the rest of the material flows away.
  4. Collect the settled particles or “black sand” and start panning it slowly to extract gold.
Crush the Rock Test to identify rocks that contain gold
Procedure to Perform Crush the Rock Test

Gold Streak Test:

Any mineral’s streak means the color it gives when observed in powdered form. Many minerals such as gold and pyrite look-alike in solid form but produce different colors when in powdered form. Therefore, the streak test is best suitable to identify real vs. fool’s gold:

  1. Take a black streaking plate or an unglazed ceramic plate.
  2. Rub the rock under consideration on the plate while applying considerable pressure. 
  3. The goal is to produce a streak of powdered material on the test plate.
  4. Results:
    • Real gold produces a yellow or gold streak color
    • Fool’s gold or iron pyrite gives a greenish-black streak.

Acid test:

Typically, gold is found attached to a piece of quartz rock and needs to be extracted using acid. This method also helps identify whether the area under consideration has a significant amount of gold or not:

  1. Place the test sample quartz rock in a container or jar.
  2. Pour synthetic kitchen vinegar (white vinegar) into the jar and make sure to submerge the rock completely.
  3. You can even use a stronger acid to speed up the process and increase the gold’s purity.
  4. Leave the jar for 24 hours to ensure all the impurities like quartz are dissolved by the acid (vinegar).
  5. If the quartz rock contains gold, you will end up with smaller chunks of gold with some quartz still attached to it.
  6. You can further purify your gold using a more powerful acid.
Acid Test to Identify gold rocks
Steps for Acid Test to identify Gold Rocks

Frequently Asked Questions

How are rocks that contain gold or white gold crystal flakes classified?

The classification of rocks that contain gold is based on the percentage of gold present in the rock. On the contrary, white gold is a synesthetic alloy of 75% gold and 25% nickel and zinc.

How do rocks that contain gold look like?

The physical appearance, as well as the weight of the rock, confirms the presence of gold in it. Rock containing gold usually have yellow veins and are heavier than other rocks of similar size.

Where to buy rocks that contain real gold in them?

Many online stores such as eBay & Amazon sell rocks with gold in them. You can also visit a rock shop to buy untreated rocks.

Conclusion

Gold traces can be found anywhere in the world. However, you need to properly identify minerals to extract a considerable amount of gold. Moreover, there are a number of tests that help distinguish between fool’s gold and real gold. I hope this article has helped you get started with your gold hunting project.

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