Just looking at a picture isn’t an accurate way to identify a crystal or mineral. There are times we can identify based on color and shape but to be more certain, it is recommended to learn how to do some mineral identification techniques. I highly recommend joining a mineral identification group if you are on Facebook for more support on this subject. But here are a few tips to get you started.
Color
Color is something to look at, however is not the best method for identification. In fact, it's one of the most inaccurate methods, especially looking at pictures. Think about how colors look differently on a phone versus computer, and so on. In addition, there are many crystals with the same or similar color and a mineral often grows in many different colors. There are so many green crystals, for example and just looking at a tumbled green stone, it could be jade, green aventurine, serpentine, and many others.
Streak Test
The streak of a mineral is the color of the powdered mineral. The color may include: white/colorless, green, gray/black, red/orange, gold/brown, blue. Most light colored, non-metallic minerals have a white or colorless streak, as do most silicates, carbonates, and most transparent minerals. The streak test is most useful for identifying dark colored minerals, especially metals.
For minerals that are harder than the streak plate, this test cannot be used, since the mineral will remove tile material. A streak plate is about 7 on the Mohs scale. The test is usually performed by scraping the mineral across a piece of unglazed porcelain underside of a ceramic tile.
Mineral and Crystal
Streak Test
Lapis Lazuli Vs Sodalite
Streak Test
MOHS Hardness
Friedrich Mohs, a German mineralogist, developed a hardness scale in 1812. This was created to assist with the identification of minerals and ranges 1 being the softest (Talc) to 10 being the hardest (Diamond).
The scale is as follows:
1 Talc
2 Gypsum
3 Calcite
4 Fluorite
5 Apatite
6 Orthoclase
7 Quartz
8 Topaz
9 Corundum
10 Diamond
Some minerals are magnetic such as Lodestone. See if your mystery mineral is magnetic by placing a magnet next to it.
Acid Test
Some minerals contain carbon and oxygen and will have a fizzing action when vinegar or HCL is applied. HCL is hydrochloric acid and should be handled with care. If you do not have HCL, then try vinegar. I recommend trying vinegar first anyway. Drop one or two drops of vinegar onto your mystery mineral and look for any fizzing reaction. Please note that the vinegar is a mild acid and the fizz action isn't as prominent as it would be with HCL. I use a magnifying glass and good lighting to look for the fizzing. It's also important to note that this test works best with a rough specimen. If there is no fizz, then try HCL. Any fizzing action will tell you that your mineral is a carbonate. I use this test to help identify Calcite. Other possibilities include: Aragonite, Dolomite, Azurite, Magnesite, Rhodocrosite and others. Check out this video where I show you how to perform the acid test.
Most crystal folks really have no interest in mineral identification techniques. I totally understand that! But it is important to have some knowledge, especially when purchasing crystals and minerals. A great tip is to research. Look up: How to identify......(and fill in the blank). For example, "How to identify Jade". You will find wonderful articles with tips. A great resource for the physical characteristics of crystals and minerals (hardness, streak, chemical composition, etc.) is http://www.mindat.org/
CRYSTAL FAKES
Let's be honest, there are so many crystal fakes out on the market today and that causes a lot of concern for buyers (rightly so). There are various levels of fake and the term is thrown around a lot, but to me, the worse kind of fake is when you are told something that is just not so. For example, when you think you bought Moldavite but you bought green bottle glass. Or when you buy expensive Calsilica and learn it's just car paint. YUCK! Or your perfectly clear "Quartz", is plain old glass. Or your bright blue Agate is dyed. I can go on and on.
This is a page that I will add to, but for now, please educate yourself before purchasing crystals and minerals. Here's a few great resources to get you started!
In addition, Hibiscus Moon has many articles regarding crystal fakes and how to spot them. Plug "Crystal Fakes Hibiscus Moon" into your browser and you will see many blog posts regarding this important topic.
Other Things to Consider