There are three kinds of people in this world. One kind, finds everything interesting and the other kind finds very little to be of interest. Curious people that discover wonder everywhere they look are well-informed but not experts, they are not jaded by repeated exposure, or by deep study of it to the point of deconstruction to better comprehend its provenance, so that much wonder falls away. By contrast, another group of people find almost nothing interesting unless it reflects upon them because they carry the burden of narcissism, which must be constantly fed because it has a voracious appetite for self validation. Clearly, you find this rock interesting and so do I, but the park curators may show less enthusiasm.
Why not take a few closer photos in better light, both wet and dry, and call it a day. The way that the 'cracks' propagate reminds me of parched clay. It could be that the parent rock did indeed crack and the cracks were filled with a slurry of silica (pulverized quartz and feldspar in water) and then as the temperature and pressure changed the slurry crystallized as a meandering inclusion. Since both the inclusion and the igneous parent rock are hard they weathered at a comparable rate thus resulting in a smooth, well-rounded beach rock. You were attracted by the pattern of light and dark and this arrangement is no less view-worthy by knowing it exact origin. I can definitely tell one thing for sure. This rock didn't come from Amazon, or from outer space. It probably did not fall off a truck and it might look pretty cool in your garden ... but then only you would get to see it. On the beach everyone gets to see it, except the narcissist, who probably trips over it while taking a selfie. Here's a thought ... maybe that's why the rock is on the beach in the first place.
