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the bedrock

dolostone

limestone with magnesium · slow to fizz

dolostone, illustrated

The tell

Looks exactly like limestone, and the difference is in the fizz. Vinegar on limestone bubbles right away; on dolostone it barely stirs unless you scratch the spot to powder first. Slow to fizz is the whole tell.

This is the bedrock up north: Door, the Straits, Drummond, the Bruce. On the Bruce Peninsula the shore is a national park, so look all you want and take nothing.

What it gets mistaken for

The facts

Put it on the shelf

Every stone on this chart is drawn and kiss-cut at three inches. The rarer the stone, the fewer exist: only 1000 dolostone will ever be printed, then the run is retired.

pick any three · $15 log your finds · free

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