Rock Sample Dichotomous Key

Rock sample dichotomous key

This dichotomous key separates four rock samples using observable texture and one simple test. A glassy surface points to obsidian. For the other rocks, a dilute-acid reaction distinguishes limestone. Visible sand-sized grains indicate sandstone, leaving granite as the crystalline, non-fizzing sample. The questions are arranged so each one narrows the remaining options. In a classroom, explain safety before using acid and substitute a different property if testing is not appropriate. Real rock identification can require additional observations, but a short key is useful for learning how classification decisions work. It gives readers a concise reference they can reuse when discussing the result with colleagues.

Type Decision treeStandard Howard-Raiffa / CART-sklearn / taxonomyEngine schematex-decisiontreeUpdated 9/24/2026

The request

“A dichotomous key to identify obsidian, limestone, sandstone, and granite samples using glassy surface, acid reaction, and visible sand-sized grains.”

Then tryAdd a shale sample outcomeReplace the acid test with a hardness test

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