Is it fossil or just a rock?

[Alex Gu]

Yesterday I bought a fossil box from the local natural history museum, just for the sea urchin inside. And there is a mysterious thing inside that looks like fossil but I've never seen something like this. Maybe it's just a weird looking rock? 

[Plantguy]

Thats a sea urchin spine...could belong to the sea urchin you have or be from another type..pretty cool!

 

What's the sea urchin look like? Did they give you any other info like its name/genus/species, its age and perhaps a location that it came from? 

 

Regards, Chris 

[Alex Gu]

Unfortunatly there are no tags or any information inside the box. But these fossils are definitely not come from China. All things in the box are two sea urchins (Pic 1, a Cidaroida sp. I think) , another sea urchin I've just cleaned by HCl (Pic 2), a Pleurotomaria sp.（Pic 3）, a Nassariidae sp. (Pic 4), some Turritella sp. (Pic 5),  some morocco shark teeth（Pic 6), a Orthoceras sp.（Pic 7),and a Crinoidea sp. （Pic 8）

[Alex Gu]

Ooops，Pic 2 is the Cidaroida sp. and Pic 1 is the sea urchin I cleaned by HCl

 

[hemipristis]

1 minute ago, Alex Gu said:

Ooops，Pic 2 is the Cidaroida sp. and Pic 1 is the sea urchin I cleaned by HCl

 

The spine looks like one from a Cidarid, though I"m not an echinoid expert