# Natural Crystal Frequencies

## Main Question or Discussion Point

If I am correct, crystal frequencies depend on the size, shape/cut, and purity of a crystal(?)
How can you measure (what instrumentation) the frequency/ies of a natural crystal (other than just quartz)?

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In the same way you'd measure vibrations in any other material.

Using a device capable of detecting vibrations - would need to be fairly sensitive. Sort of like the ones they use to sense heartbeats on lorries crossing the channel.

I can't, for the life of me remember the name of them.

Really???
I'm looking for solid answers and don't have time to read useless posts.
Your's really didn't help at all.
I knew that much on the subject.
Please... if all you want to do is hear yourself speak, do it in private, or at least write meaningless posts on someone else's thread.

Welcome to PF MaterSammichM.

You will soon learn that your attitude isn't acceptable here and people won't bother responding to you if you take that stance.

Google "vibration sensor" and you'll find a whole host of equipment capable of achieving your task. If you're too lazy to do this then that is your problem not mine.

Cut the attitude.

EDIT: Oscilloscope that's the one. You'll be need one of those too. Possibly something involving ultrasound would be a good choice.

If I am correct, crystal frequencies depend on the size, shape/cut, and purity of a crystal(?)
"Crystal frequency" is quite meaningless by itself. It can refer to (at least) several different things.

If you mean mechanical resonant frequency, you can either calculate it (if the shape is nice) or measure it by simply vibrating the crystal and measuring the response versus frequency. The frequency (or frequencies) where you get maxima of the response are the resonant frequencies.
You can vibrate the crystal with a piezoelectric chip or speaker attached to a signal generator and measure the response with a microphone, an ultrasonic transducer, etc., connected to oscilloscope.
There are some catches. The resonance depends on the way you support the crystal (at one end, in the middle, both ends, etc) as well as on the size, shape, material.