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Strike versus streak
Short answer
Strike is the compass direction of a horizontal line on an inclined bed, used in structural mapping. Streak is the colour of a mineral's powder obtained by rubbing it on a streak plate, used for mineral identification.
Differentiate between strike and streak.
These two terms belong to different fields: structural geology and mineralogy.
| Basis | Strike | Streak |
|---|---|---|
| Branch | Structural geology | Mineralogy |
| Meaning | Direction of the horizontal line on an inclined bed or plane | Colour of the powder of a mineral |
| Defined by | Intersection of the bed with a horizontal plane | Rubbing mineral on unglazed porcelain |
| Measured as | Compass bearing (azimuth) of the line, e.g. N 40° E | Colour name, e.g. red-brown |
| Instrument | Clinometer compass | Streak plate |
| Related term | Dip (at right angles to strike) | Colour (may differ from streak) |
| Use | Mapping, slope and tunnel stability | Mineral identification |
| Example | Bed striking N 30° W, dipping 40° NE | Hematite: red-brown streak; pyrite: greenish-black |
The strike of a bed is always at 90° to its true dip direction. Streak is more reliable than the colour of a mineral because it stays constant.
✓ Answer checked by Claude Opus 5.5 (high effort)
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