Identification combines independent observations and tests competing possibilities. A test should distinguish candidates that otherwise look similar. The model uses published reference hardness values and clearly labelled virtual results, not laboratory measurements of the illustrated crystals. A single result can eliminate some candidates without proving a unique mineral identity.
Earth and geology · Discover & try
How can tests distinguish minerals?
Reading level 5 of 5 · AdvancedChange
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Hardness
Relative resistance to scratching.
Streak
The colour of a mineral’s powder on a streak plate.
Lustre
How a mineral surface reflects light.
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See how it works
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Virtual tests and reference properties; original crystal drawings are not measured specimens or a complete identification key.
What to look for
- Use a harder and a softer reference.
- Compare the remaining candidate set.
- Do not treat the Mohs scale as a linear ratio.
Explain what you noticed
An unfamiliar specimen scratches calcite (3) but is scratched by orthoclase (6). What is supported?
Keep this idea: Several properties are more useful than colour alone, and hardness describes scratching resistance.
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