Is this a blister pearl?

[jbrew]

Hello. Can anyone help me identify this pearl? I'm assuming it's a pearl. It's on a diamond brooch. Thanks!

 

[Pearl Dreams]

What an interesting pearl! Could be natural. How old is the brooch-- do you have any idea?

 

[jbrew]

It's set in platinum with old cut diamonds. As far as I know it was my wife's great grandmother's pin. I can't seem to find another pearl (google images) that's lumpy like it.

 

[Pearl Dreams]

Looks to me like a clever use of a natural pearl to resemble a rosebud in the brooch. Very cool!

 

[amti]

Please show the entire brooch. I'm curious to see it. It looks lovely! Is that gold sticking out of the hole?

 

[Orient]

Hard to say from the images provided. As already mentioned by Pearl Dreams it looks like a rosebud pearl so freshwater and as amti notes there is some embelishment on a surface reaching feature (surface blemish?) where it could have been in contact with the host's shell. That doesn't mean it would be classified as a blister pearl as most blister pearls or blisters have to be cut from the shell to use as "loose" pieces. Does look like an interesting piece of jewellery and if it is linked to your wife's great grandmother it is likely natural as has also been noted by Pearl Dreams.

 

[parfaitelumiere]

Where are you located?
It may be a freshwater pearl, it seems these were really common in USA, Mississippi and Tennessee, because of mother of pearl industry I would say from second half on XIX to maybe the 60's or so.
I have a whole collection of freshwater pearls from turn of century and some have really weird shape and design.
It's possible to find some mounted on jewelry, even very high rank Jewelry like Tiffany, There were several brooches made using typical petal shaped freshwater pearls, and used to make chrysanthemus flowers, mounted on platinum, so yours could be same maker, and same style.
Flower theme is a really old jewelry tradition.