Which would you prefer to find a mold or a cast?

[OregonFossil]

Which do you prefer to Mold or Cast - Why?

 

Secondary question is have you ever used a vice to break shale or sandstone? I started do this and seem to get good results.

[Harry Pristis]

A mold is a void.  A cast is a 3-D representation of the interior or exterior of the actual fossil.  A ready-made cast is usually preferable to making your own cast from a natural mold.  There are exceptions, as in the case of a natural external mold.

[Fossildude19]

For me, it depends.  I like casts of shells and trilobites. However, there are some molds that are extremely detailed - and those are interesting to me as well. 

I've never used a vise, but I have used a tile nipper to do some soft limestone trimming/extraction.

 

Someone not too long ago posted about using vices to break matrix. 

 

[OregonFossil]

I just stumbled upon the vice method as I restart my fossil hunting. You can feel even shale break before it cracks. I use dental tools and a dramil with small steel bits.