How To Ask For Help With Rock And Mineral Identification
By Currently Rockhounding
This article will provide some basic guidance for the novice collector of rocks and minerals that wants to ask others for help with identifying something that they found. The topics covered here will be how to take photos, the importance of location, basic specimen observations and some common mistakes people make. The more work you put into figuring out some things yourself about the specimen in question, the more likely it is you will get a correct answer from who you are asking.
It’s important to recognize that rock and mineral identification can be a very complex process at times and often more information is needed than just a photo of the specimen. With over 5,400 recognized minerals that can combine to make up an even larger number of rocks, specimen identification can get really complex and even if you do all the things described in this article you may not get a 100% positive identification.
This is not a guide on how to do complete battery of identification tests which requires many tools which most new collectors do not have. If you would like to know more about some of the tests that can be performed there is a Practical Rock & Mineral Identification guide here.
Photography
The first step in getting help online from someone or a group is to take great photos of your specimens. Places like Facebook are filled with post from people asking for identification help and the photos they posted are often dark, blurry and completely terrible. Without some good photos there’s really no point in continuing.
The perfect photo is one taken outside of a individual dry rock with a coin for scale, in the sunlight, with the rock stationary and your camera is also stationary. Take a photo of each side like this.
Things you want to avoid doing when taking photos would be taking them indoors with poor artificial light, shining a flashlight through them if translucent, wetting the specimen with water, holding the specimen in your hand and taking a photo of a pile of rocks instead of individuals.
Taking quality photos and avoiding the pitfalls of taking horrible photos will increase the likelihood of you getting the help you want a significant amount.
Location
The location where the rock was found is extremely important and I don’t mean the state or county. I mean the exact GPS location of where the rock was found. If the specimen in question was not self collected then you will be at a major disadvantage.
For example if someone said they found a rock east of Seattle, Washington and that was as specific as they’re willing to get for the location that could mean anything and they might as well have said nothing. This is what the geological units look like east of Seattle.
In a nutshell each of the colors on this map represents different geological units, and the rocks you find in one unit can be extremely different from what is right next to it.
This is the reason the location of the rock matters: only certain rocks and minerals will exist in certain units.
I know some people do not want to give away the location that they found their specimen at because they fear other people will go to the location but I can assure you that your rock is likely not that unique, rare or valuable.
Specimen Observations
The more things you can observe about your specimen and include with your question about its identity the better. We will only be focusing on a couple of the tests which are the easiest to preform. Hardness, magnetism and effervescence.
Hardness:
One method often used to narrow down what a rock or mineral is would be hardness. For rocks and minerals we use the Mohs hardness scale, which is the rough measure of the resistance of a smooth surface to scratching. This topic is big enough and complex enough that I could write a whole article on it.
In 1822 the German mineralogist Friedrich Mohs came up with a hardness scale to test rocks. This scale is a chart of relative hardness of the various minerals from 1 to 10. All rocks will be somewhere between a 1 and 10 on the scale.
This is a very a very popular chart that often makes the rounds online showing common items that you might have around your house that you can use to scratch a rock to test its hardness. This is not very precise since things like nails will have variation in them but for something that is pretty much free it’s better than nothing.
You can buy a hardness test pick set for testing rocks and minerals which will allow you to test the hardness with great accuracy. I own the Mineralab Test Kit (affiliate link) but at $120 its a lot for most people starting out.
Magnetism:
This is a very simple test to preform, all you need is a small magnet on a string. The reason for the string is you can detect very weak magnetism with this by hanging the magnet from the string and bring it closer to the specimen. When it touches the specimen, the attraction doesn’t have to be strong enough to support the weight of the magnet since you’re the one holding the weight of the magnet.
Mineral Effervescence:
This is a chemical reaction test where small bubbles of gas escape a from a liquid. This is usually caused by the mixing of two incompatible substances. Most carbonate minerals display effervescence upon coming into contact with certain acids.
This is most often done with diluted hydrochloric acid but most people don’t have bottles of that sitting around so for this we can substitute the hydrochloric acid for distilled white vinegar which is more common in the household.
The actual test is pretty simple, take some of the white vinegar and place it in a glass container, then add the specimen or if the specimen is large just apply a few small drops of vinegar to a spot on the rock and look for it to fizz, bubble and foam.
This won’t work for all carbonate minerals but it will for many of them.
Common Mistakes
Over the years I have seen a lot of ‘What is it?’ posts and have received many emails asking for help with identification.
Here are some of the common mistakes and pitfalls I see people repeatedly making.
1. The weird looking rock you have that’s magnetic and you think is a meteorite is not a meteorite.
2. The green rock you found is not jade.
3. The rock you found with little golden specs on it is not gold.
4. The egg shaped rock you found is not a petrified dinosaur egg.
5. The small clear rock you found is not a diamond.
6. The rock you found with banding on it is not necessary petrified wood.
7. The rock you found that looks like a tooth, bird, lizard, fish or some other living thing is not a petrified version of that.
8. The rock you found with what appears to be a dinosaur track on it just looks like that and was not stepped on by a dinosaur.
9. The rock that looks like poop is very likely not coprolite.
10. The chipped up agate, jasper or obsidian you found is very likely not a native American artifact.
Yes meteorites, jade, gold, dinosaur eggs, diamonds, petrified wood, fossils, dinosaur tracks, coprolite, and knapped artifacts all exist but the likelihood of you finding them without purposefully searching for them in an area known for them and already having an idea of what to look for is very slim. When I see someone with very little experience claiming they found any of these things 99% of the time they’re wrong.
You don’t have to take my word for it, many university geology departments will preform identification of specimens for free to the public.
Conclusion
I hope you found this article to be helpful and if you follow these steps you’re much more likely to receive an accurate identification for your rock or mineral but it’s not a guarantee. The only way to be 100% sure of an identification is going putting your specimen into the hands of someone who is a very serious hobbyist when it comes to identification or a university geology department.