Say an emerald inside a spinal inside an opal inside plain old limestone or something like that.
Not necessarily as neatly stacked as Russian dolls, but it is possible for gemstones to be formed together and to intermingle or be completely enclosed as inclusions
You can get garnets and rubies in diamonds. (Google images)
Inclusions. I like those photos. Beautiful stones, if a bit quirky.
The geochemistry of garnet inclusions in olivine (peridot) inclusions in diamonds was actually the topic of a master’s degree of a guy I know. Or they were olivine inclusions in garnet in diamond, something like that. Anyhoo, they could help tell a great deal of the genesis of that particular diamond pipe (IIRC it was a Canadian one)
But we’re talking smaller than a grain of sand, here.
The family-sized version of that would be awesome. A clear diamond with a pale green stone inside that has little blood spots here and there.
I read about that big-ass opal that just sold for $144,000, and I thought how weird it would be if they cut it years from now and found a million bucks worth of diamonds inside it.
Yes, that would be very weird, given that the two form under completely different conditions.
It’s not a requirement that the stones be the same age.
Largely forgotten – and fictional to boot – the Pink Panther started out as large diamond with a pink inclusion that looked like a leaping panther.
Opal is a secondary mineraloid that can occur with a wide range of host rocks, and does have inclusions (including insects) so can very possibly occur in a diamond-hosting volcanic.
But if a diamond was in there, it would be a very unusual pure coincidence. You could find a diamond in a Mazon Creek nodule, because there could have been a diamond source somewhere within range to be washed into the water. But you probably won’t.