A Few Tips on Identifying Minerals BEFORE Bringing It to the Rock Shop for Help:
Every single day there is at least one person who comes into the shop, hands us a mineral and asks “can you help me identify this?” Most of the time when we ask if they can tell us anything about the specimen we usually get an, “I don’t know, I just found it or it was given to me.” However, not knowing anything about the specimen doesn’t help us help you! Therefore we’re going to outline a few things that you can do at home to give us some info about your specimen. This saves time on both our ends and stays true to the saying, " Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime".
First What is the locality of your specimen? Knowing where your specimen comes from really helps narrow down the types of minerals that occur in and around that particular locality. You can use that info to do a quick search online for associated minerals in that area. If you don’t know the locality of your specimen, because it was given to you with no information, don’t lose hope! There are other ways you can narrow down what your specimen may be.
Second What is the hardness of your specimen? There is a scale called the Mohs Hardness Scale. It is a scale that characterizes the scratch resistance of minerals. Simply put, harder minerals scratch softer minerals. Testing hardness is actually pretty simple using common items you can find around your home. A masonry drill bit(8.5), steel nail(6.5), glass(5.5), a penny(3.5), and your fingernail(2.5) are all items you can use to test your specimen. They are assigned numbers, the higher the number the harder it is.
What you are testing for is if one of these items scratches your mineral, or if the mineral is scratching the item. For example, quartz is harder than glass therefore it will always leave a scratch on a piece of glass. Here is a link to a video that briefly shows how to test hardness, https://www.youtube.com/watch?v=R-bw7_u3gSQ&app=desktop Once you test harness you’ll be able to narrow down whether you have a diamond or just a piece of slag glass.
Third What streak color does your mineral have? Streak describes what color the powdered version of your mineral is when scratched on an un-glazed porcelain white tile. Sometimes the streak color can be completely different than the color of your specimen, like in the case of hematite. Hematite’s streak color is ALWAYS red no matter what color the hand specimen is. Pyrite is similar in that it’s usually gold in color but it’s streak is always black.
You can typically get a tile at a local art store, pottery studio, or even order one online. This test can really help you distinguish if you have a piece of gold or pyrite! Here’s a link with a list of the streaks of some common minerals https://geology.com/minerals/streak-test.shtml
There are many more tests that can be used to help identify minerals but these three are simple and can really help us help you narrow down what your mystery specimen may be. Coming into the shop with this information is so helpful! So please in the future if you don’t know what you have, just know that there are better ways to find out than just handing it to us with absolutely no information on it.
Acid tests, magnetism, luster, crystal form and mineral habit are just a few other factors that can be tested to aid in the identification of a mineral. Learning some of these can be quite comprehensive but it’s worth giving it a gander online. Because any information that you can give us about your specimen is so much better than no information at all!
If you’re interested in learning more about how to identify minerals send us an email and we can provide you with some pretty good resources. We also have an educator box that has some specimens and testing materials to help you understand how to do the tests to identify the minerals within it and any other specimens you have in your collection.
Peace out rock nerds! #doitfortheGRAM