I'm upgrading my husband's wedding ring and I would like to have our kids' birthstone (sapphire and emerald) set inside the shank. In general, how big are the surprise stones?
With coloured stones, they all have different specific gravities, so it's best to ask your jeweller to get the stones in mm sizes rather than carat points.
Also best to have the jeweller source the stones as they have suppliers that don't deal with the public that stock this kind of thing by the kilo!