You're not giving us much to work with.
Your rock is translucent, it passes some light but not clear like glass (transparent).
Rocks don't feel soft. It might feel waxy or greasy. Try to scratch it with a nail, piece of window glass, then a piece of known quartz. Let us know which, if any, of them scratches it.
Based just on your pictures it looks like a piece of flint.
No guess on the second rock. Take more pictures, do a hardness test.