How to identify a geode.. definitely MMPS

Backstory: I helped out a friend with moving house, she gave me a small quartz (?) rock as a thank-you - she’s not exactly wealthy, and I did the move for free (with her help). I don’t know the backstory, but I am pretty confident she was given it as “a geode” and gave me something she thought was a good gift.

Anyway. I now have a 4cm x 3cm x 2cm irregular rock. It looks like quartz to me but I am no minerologist. It is quite worn on the surface, but I think I can see worn down crystals on the surface.

My kids, aged 10 and 7 3⁄4 are interested in many things, but science and rocks are amongst them, so if this is a geode, I would like to get it cut open.

So, if some geologist suggests it is worth taking to a place that can cut it open, I’ll do that. I have quite a lot of doubt that it is anything but a common or garden rock.

Pics

From what I recall, the biggest indicators are weight and rattle. Find a rock of similar size and see if your’s weighs quite a bit less. If you hear something rattling inside, that’s almost a sure indicator. Geode or ordinary rock; what is the downside of slicing it open beside the expense?

There is no rattle.

There are a couple of places that sell rocks, from tumbled pebbles up to 6 foot tall geodes in my city, so maybe I ask for an assay - or maybe they could just cut it, I don’t have equipment. Nothing to risk except mild disapointment!

Do it yourself.