There is. There are hand held spectrometers that can tell very reliably. But they're still rather expensive.
But the better question is "is there an inexpensive non- invasive way to check if something is aluminum"
The only thing I can think of would be measuring the density. Calculate volume, weigh and compare to what a bit of aluminum that volume should weigh. It would take some accurate equipment, but it would be fairly reliable and wouldn't damage the plate.
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