Field Notes · January 2026
Identifying Minerals in the Field
“You don’t need a lab. You need your eyes, your hands, and a little patience.”
One of the most common questions I get is: “How do you know what you’ve found?” The honest answer is that field identification is part science, part experience, and part gut. But there’s a reliable process I use every time — and you can learn it too.
The Five Tests
These five observations will get you 90% of the way to a correct identification for the minerals common in BC.
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1. Colour
The most obvious — but the least reliable on its own. Many minerals share colours, and the same mineral can appear in many shades. Use it as a starting point, not a conclusion. Quartz can be clear, white, pink, purple, or black.
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2. Streak
Drag the mineral across an unglazed porcelain tile (streak plate). The powder colour is often more diagnostic than the surface colour. Hematite looks silver or red — but always leaves a red-brown streak. Pyrite looks gold — but leaves a greenish-black streak.
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3. Hardness
Use Mohs scale. Your fingernail is ~2.5, a copper coin ~3, a steel knife ~5.5, quartz ~7. Scratch the unknown mineral with each tool to bracket its hardness. This eliminates most false positives — real gold is soft (2.5–3), pyrite is hard (6–6.5).
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4. Lustre & Transparency
Is it metallic (like pyrite), glassy (like quartz), waxy (like jasper), or pearly? Hold it to the light — is it transparent, translucent, or opaque? Agate is translucent. Jasper is opaque. Same silica family, very different light behaviour.
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5. Fracture & Cleavage
How does it break? Quartz fractures conchoidally (smooth, curved surfaces like broken glass). Feldspar cleaves in flat planes. Mica peels in perfect sheets. A fresh break tells you a lot about crystal structure.
Common BC Minerals at a Glance
| Mineral | Colour | Hardness | Streak | Key Clue |
|---|---|---|---|---|
| Quartz | Clear/white/pink/purple | 7 | White | Glassy, conchoidal fracture |
| Jasper | Red/orange/yellow/brown | 6.5–7 | White | Opaque, waxy surface |
| Agate | Banded, various | 6.5–7 | White | Translucent bands, waxy |
| Amethyst | Purple (quartz variety) | 7 | White | Crystal points, purple hue |
| Pyrite | Brassy yellow | 6–6.5 | Greenish-black | Cubic crystals, metallic |
| Garnet | Red/brown/orange | 6.5–7.5 | White | Dodecahedral crystals |
📱 Field App I Use
Rock Identifier (iOS/Android) is surprisingly good for cross-referencing in the field. But trust your hands and tests first — photos can mislead.
The more time you spend handling stones, the more intuitive this gets. There’s a feel to a good piece of jasper that’s hard to describe but unmistakable once you know it. That’s the part no guide can teach you — only the field can.
Found something and not sure what it is?
Send me a photo — I’m happy to help identify it.