Bart Cannon’s Advice on Mineral Identification
In this article I would like to share with you and discuss a post that was made by the legendary mineral collector, author (Minerals of Washington), rockhound and prospector Bart Cannon.
Bart posted this on the now closed NW Rockhounds Facebook group which had 26,000 members and to say the least it was not well received. You don’t have to look for very long at any of these Facebook groups to see how common it is for someone to take a blurry photo of a rock and post it asking what it is with no other information. Bart Cannon pointing out the flaws in doing this upset those who do just that.
I agree that his post lacks the sugar-coating that is now commonplace on the internet but that doesn’t make the information any less valuable.
The advice Bart Cannon shared within this post is golden in my opinion and should be archived for the future in its unedited glory but it’s also starting to show its age a bit so below I will provide my own updated take on some of his recommendations.
I’ve been following NW Rockhounds for quite a while. The group in general needs to be taught or self educated about mineral identification, occurrence and association.
Rocks are NOT minerals. Minerals compose rocks. Minerals are chemical compounds which show crystal structure. There are 5000 different mineral species. There are probably about 50 that the hobbyist will encounter. Get to know them. Start a reference collection. Buy some books such as “Mineralogy for Amateurs” by John Sinkankas. It is the best authoritative text which can lead to an understanding of mineral species and their characteristic habits and mode of occurrence. Good black and photos and line drawings including crystal forms. Another good book is “Minerals” by George Robinson. He does an excellent job of explaining how and where minerals form and occur.
Buy an inexpensive stereo microscope. You can get a decent one from Amscope for about $150. It that’s too expensive buy a hand lens such as a Hastings triplet. A stereo microscope is an entrance to a whole new world. A new view of your cuticles and “bud” is only a start, but a stereo microscope can’t be beat for minerals. Buy a short wave and long wave ultraviolet light. Mineralogical Research Company in San Jose has a complete selection. You can find more inexpensive pricing at various sites.
A geiger counter is a good identification tool. I have a durable light weight one from Radiation Monitoring Devices. $350. Pretty expensive. search the internet for a Victoreen CD 700. I bought one years ago for $29 at Hardwick’s Swap Shop.
Most experience mineral people can identify the common minerals species by hand and un-aided eyeball. Many require a stereo microscope and a dropper bottle of hydrochloric acid to see if it bubbles when exposed. That means it’s a carbonate.
Put together a Moh’s hardness kit. Cheap to do. Also a rough back of a ceramic tile is good for a scratch test. Tough cases require more advanced techniques. The least desirable method is posting a “what is this” on Facebook..That should only be done after the individual has made a good effort to identify it with their own hard won skills at mineral ID. If you are lucky you know a good mineral ID person who will probably able to conduct a good ID on sight with specimen in hand. Rarely I see specimens that are so diagnostically typical that Facebook will work.
I have an advance lab dedicated to tough IDs. I use electron microprobe, x-ray diffraction and polarized light microscopy. It’s too expensive for any but the most serious hobbyist.
Good luck. Most people can, with some effort, become actual mineral people.
Not that this post is monumental in anyway, but it might be worth printing and saving. I’m happy to answer questions about mineral identification and will take a look at a specimen through the stereo microscope. I am writing the second edition of my old “Minerals of Washington”, and I may conduct some sophisticated IDs at no charge if the approximate location in Washington state is provided.”
Bart Cannon
Now to address some his suggestions made in his original post.
The books he suggestions I think at the time when they were published were quite good and I have the book Minerals by George Robinson but it leaves a lot to be desired when compared to more modern publications on the subject. I have here on the website a library section with all the books I personally own that I find to be valuable and recommend.
The advice Bart Cannon gives on the subject of microscopes is advice that I wish I had taken sooner. He suggests buying a microscope or at least a jewelers loupe if you can’t afford a microscope.
My microscope I have is a trinocular stereo microscope, with 3.5X-180X magnification produced by AmScope (affiliate link). The size and magnification on this microscope along with the ease of attaching a camera to it makes it a perfect choice for rock and mineral identification but it’s also a bit pricey at about $800. Realistically, I have found that most the work I do with the microscope is in the magnification range of 10x-80x which means you do have some more affordable options available for stereo scopes such as this one from AmScope (affiliate link).
On the subject of ultraviolet lights his advice to buy them is of course helpful and correct. The price of 365NM longwave lights has really came down in recent years and a good light can run between $40-$80. However, shortwave lights are still really expensive, bulky, and fragile.
I agree that a Geiger counter is a good identification tool and I personally own one but for many people it’s really not needed. Most people do not accidentally collect radioactive rocks and it really is something that you need to be looking for and trying to add to your collection if you want it. Also, most naturally occurring radioactive specimens are not as bad as you think they are. For more information about radioactive minerals, I highly recommend reading Here be Dragons: The Care and Feeding of Radioactive Mineral Species by Alysson Rowan which available for free.
I’m not sure what the availability was of a legit Mohs hardness test kit when Bart was writing his post but putting one together is less than ideal and will not give you the same results as a purchased pick set. I have the field testing kit from from MineraLab (affiliate link) which comes with everything needed to test the hardness of a rock or mineral. The hardness pick set is an essential tool to have when it comes to identification.
I think the takeaway from this should be that the very notion that you can identify everything based on a photo is a flawed concept and perhaps Bart Cannon said it best when he wrote “The least desirable method is posting a ‘what is this’ on Facebook..That should only be done after the individual has made a good effort to identify it with their own hard won skills at mineral ID.” It might be harsh but it certainly isn’t wrong.