Tagged “durability”
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Marble, calcite, and the soft white stones
A white or honey-banded tool is very often a carbonate: soft, cleavable, and the one material a household acid identifies outright.
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Testing a stone at home
The scratch test, the water test, the loupe and the kitchen scale — what each one actually establishes, and the much longer list of what none of them can.
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Hardness, toughness, and why tools break
Hardness resists scratching. Toughness resists fracturing. They're different properties, and the harder stone is often the one that snaps.
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Horn, bone, and wood as tool materials
Organic tool materials behave nothing like stone: they take up moisture, move with it, and soften with heat rather than cracking.
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Stainless steel and metal tools
Steel does not fail like stone. It bends instead of shattering, and the interesting question is whether a metal tool is solid steel or a plated casting.
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Why stone feels cold
A stone at room temperature is not cold. It feels cold because it conducts heat out of your skin faster than your skin can replace it.
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How a stone tool is cut and polished
Every stone tool passes through sawing, shaping, a sequence of finer abrasives and a polish. What the workshop skipped is usually visible on the object.
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Veins, inclusions, and internal lines
The lines inside a stone are its history. Some are healed structures the material grew around; others are open cracks waiting to finish the job.
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Amazonite and the feldspars
Amazonite is a green potassium feldspar, and feldspars have cleavage — planes of weakness that no amount of hardness compensates for.
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Obsidian, and natural glass
Obsidian is volcanic glass — genuinely amorphous, genuinely a stone. Which makes it the one material where looking like glass proves nothing.
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Serpentine, the stone most green tools are
Serpentine is a mineral group, not a species, and it is what a large share of inexpensive green stone tools are made from. Here is how it behaves.
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Crystalline, microcrystalline, and amorphous
Whether a stone is one crystal, a mass of tiny interlocking ones, or no crystal at all explains how it breaks, how it shines, and how light passes through.