Don’t try this in California
Ninja rocks. They are neither ninjas nor rocks.
They’re little bits of aluminum oxide ceramic, like the insulator on a sparkplug. Even a small piece flung at tempered glass will make it shatter thoroughly and relatively quietly (that’s the ninja part). Ideal for smash and grabs.
So much so that California has declared them de facto burglary tools. A court in Washington state accepted posession as proof of intent to burgle.
It works because aluminum oxide is very hard and the surface tension of tempered glass is very high. On the Mohs scale of mineral hardness (which measures the ability of one mineral to scratch another), diamonds are 10, aluminum oxide ceramic is 9, tempered glass is 6.5. So a light blow with a very hard object breaks the surface tension of tempered glass and makes it do what it’s supposed to do: shatter into a kzillion tiny relatively harmless pieces.
I suppose it would work even better if you threw diamonds, but that would probably miss the point of a smash and grab.
Plenty of video on YouTube. Like here (warning – extreame).
February 13, 2012 — 9:36 pm
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