2.1 Identification of Minerals

Nowadays, mineral names are based on mineral appearance, mineral chemistry, where the mineral is found, a famous scientist, or anything else deemed important by the mineral’s discoverer. The naming of minerals has changed over time from alchemistic beginnings to the advanced science of today. You will notice that many mineral and rock names end in ite?” The suffix “ite” is derived from the Greek word ites, the adjectival form of lithos, which means rock or stone.

In antiquity, distinctive physical characteristics, such as colour, were used to name a mineral. For example, garnet comes from an old French word, grenate, for blood-red. Two minerals with similar composition are malachite and azurite (both Cu₂CO₃(OH)₂). Malachite comes from the Greek word malakee or malache, used to describe the green leaves of the mallow bush. Azurite comes from azure, the Arabic word for blue. Another blue mineral is kyanite, which comes from kyanos, the Greek word for blue. Some minerals have been named for their chemistry or their structure. For example, cavansite is named for its chemistry (calcium vanadium silicate), and pentagonite is named after a five-sided pentagon.

So, if you suspect you have a new mineral, your proposed name gets approved by the Commission on New Minerals, Nomenclature and Classification part of the International Mineralogical Association (IMA). Also, as of July 2023, the Handbook of Mineralogy lists 5,663 species, and the IMA Database of Mineral Properties/Rruff Project lists 5,956 valid species (IMA/CNMNC) of a total of 6,189 minerals. Fortunately for you, there are just about a dozen mineral names that you should learn to recognize. See the appendix for the origin of the common mineral names.

Identification of Minerals

The correct identification of minerals is necessary for characterizing rocks and identifying mineral resource potential. It is fundamental to the study of geology. The minerals that you will be expected to learn here are some of the more common rock-forming minerals and a few of the important minerals from the world of mineral exploration and mining.

You will use a second set of minerals provided during lab time, the simple tools that you used to test physical properties, and the information provided here to name each of the minerals. Your TA will review the correct names with your lab section after students have had an opportunity to attempt naming the minerals. Your lab instructor may also set out a practice test along the side counter for additional practice. The worksheet at the end of this section is meant to help you use physical properties to distinguish between some mineral species.

Minerals and Their Chemical Compositions

Minerals are grouped according to their chemical compositions. All minerals (except native metals) are grouped first by their anion composition (i.e., silicates, carbonates, oxides, sulphides, sulphates, halides). Students are expected to learn the following minerals and their chemical compositions listed in Table 2.1.

2.2 Process of Mineral Identification

Minerals are identified based on distinctive physical properties, using a systematic approach. While many methods exist—like textbook flowcharts or online tools—this lab uses customized identification sheets tailored to your sample drawer (Table 2.2). This is the flow:

1. Lustre and Colour
Begin by identifying whether the mineral has a metallic or non-metallic lustre. Then, classify its colour as light or dark to choose the correct identification sheet. This step quickly narrows down possible minerals in your set.

2A. Metallic Minerals: Streak and Hardness
For metallic minerals, use the streak test to categorize them into groups based on their streaks: dark, red or red-brown, or yellow. If the streak is dark, test the hardness and use other traits, such as colour and cleavage, as needed.

2B. Non-Metallic Minerals: Hardness and Cleavage
Non-metallic minerals are more common and often harder to identify, especially light-coloured ones that may look similar. Focus on hardness and cleavage, and make detailed observations to distinguish between them.

3. Final Identification
After narrowing it down, use the remaining physical traits to confirm the mineral. If things don’t match perfectly, you may have misidentified a property, like missing cleavage in a fine-grained sample. Don’t hesitate to backtrack and try a different path in the flowchart. These tables highlight the most common and diagnostic properties, but feel free to expand or adjust the notes to support your learning.

2.3 Critical and Strategic Minerals

If we know so much about minerals, why do we continue to study them? The answer is simple: Minerals are often essential resources used to improve our lives. More specifically, critical minerals are the basis of modern technology and are essential to the production of many useful items.

To be considered critical, according to the Government of Canada, a mineral must meet both of the following criteria:

• The supply chain is threatened
• There is a reasonable chance of the mineral being produced by Canada

It must also meet one of the following criteria:

• Essential to Canada’s economic or national security
• It is required for the national transition to a sustainable, low-carbon and digital economy
• Position Canada as a sustainable and strategic partner within global supply chains
  

There are 34 critical minerals in Canada, although we have a focus on six, specifically lithium, graphite, nickel, copper, cobalt, and rare earth elements (REEs). You’ll notice that these critical minerals are just element names. Many elements do not occur freely in nature, and naturally occurring deposits of pure elements are rare on Earth. Instead, these elements are incorporated into the chemical composition of minerals, which must be mined and processed to extract them. For example:

• Aluminum primarily comes from a type of rock called bauxite, which contains minerals such as gibbsite [Al(OH)₃], boehmite [γ-AlO(OH)], and diaspore [α-AlO(OH)].
• Lithium primarily comes from minerals such as petalite [LiAlSi₄O₁₀], lepidolite [K(Li,Al)₃(Al,Si,Rb)₄O₁₀(F,OH)₂], and spodumene [LiAl(SiO₃)₂] as well as brines (salty water which contains significant amounts of dissolved elements/compounds).
• Nickel is mainly found in laterite deposits and magmatic sulphide deposits, in minerals such as pentlandite [(Fe,Ni)₉S₈], pyrrhotite [Fe_(1-x)S], and millerite [NiS].

Additional Information

Exercise Contributions

Lab 2: Why Are Minerals Important to Canadians? was modified by Jessica Kristof and Ricardo L. Silva from the original Chapter 4: Minerals by Virginia Sisson and Daniel Hauptvogel in Hauptvogel et al. (2024) and the original Lab 2: Identification of Minerals in Ferreira and Young (2018). 

References

Ferreira, K. and Young, J. (2018). GEOL 1340 The Dynamic Earth Lab Manual. Winnipeg, MB: Department of Geological Sciences, University of Manitoba

Hauptvogel, D., Sisson, V., and Comas, M. (2024). Investigating the Earth: Exercises for Physical Geology. Houston, TX: UH Libraries