This is a beautiful slab of Mystery Agate, not sure of type. I My father collected this in northern California, I believe in the 1970's.  My father cut the large rock into slabs as pictured.   This slab is shown wet.  You will see that this almost a dark greenish blue in spots with shades of pink colors and has a pattern.   This slab is approx. 1/4" thick.  Measures 5 1/4"" at longest point and 2 3/4" at widest point.  Note: 3rd photo shows clear areas in agate with backlite. This is a solid piece. Can easily be trimmed to create cabochons or free form pieces for jewelry.