Yes from the hardness, curved fracture, and microcrystalline texture chert is the obvious identification. Of other suggestions fine micritic limestone would be much softer while jasper and flint are types of chert. read more
It certainly looks like chert. Chert, flint, agate and jasper are all very close to each other. Close enough that it can be hard to tell from a photo. read more
Chert is a fairly common rock. It is composed of microcrystalline silica, and forms originally in the deep marine environment. Bedded chert forms on the deep ocean floor from silica gel and the skeletal remains of very tiny marine organisms with siliceous skeletons (like radiolaria). read more
Chert is a microcrystalline or cryptocrystalline sedimentary rock material composed of silicon dioxide (SiO2). It occurs as nodules, concretionary masses and as layered deposits. Chert breaks with a conchoidal fracture, often producing very sharp edges. read more