Is this a mineral inclusion, or is it biological?

[Pleuromya]

Hello, I've been intrigued by this for days, and I am wondering if it is a fossil or not?

Found in Northamptonshire, UK, which is mostly Jurassic in age. I've found Bivalves, belemnites and some gastropods in the same area.

Sorry there's no scale, its about 5mm.

Thanks.

[Pleuromya]

[Pleuromya]

[digit]

Looks like a silica-rich mineral inclusion to me but we'll see what our members think who are from that area and are more familiar with the geology.

 

 

Cheers.

 

-Ken

[grandpa]

8 minutes ago, digit said:

a silica-rich mineral inclusion

I'm thinking along the same lines.  I'd add calcite, gypsum and barite as possible sedimentary mineral possibilities, depending on the geology of the area.

[Pleuromya]

25 minutes ago, digit said:

Looks like a silica-rich mineral inclusion to me but we'll see what our members think who are from that area and are more familiar with the geology.

 

 

Cheers.

 

-Ken

 

15 minutes ago, grandpa said:

I'm thinking along the same lines.  I'd add calcite, gypsum and barite as possible sedimentary mineral possibilities, depending on the geology of the area.

Thanks. 

[Planko]

I'll add calcite 

[Plax]

I think I see the radiating lines of a belemnite cross section.