High-precision, lightweight, and low-cost MEMS gyroscopes are needed in many existing and emerging applications including autonomous vehicles, drones, underwater vehicles, space satellites, and wearable motion-tracking devices. We developed a novel fused silica three-dimensional shell resonator called the micro birdbath resonator and the micro birdbath resonator gyroscope (BRG).  The micro birdbath resonator has Q as high as 12.5 million at 12.798 kHz.  A vacuum-packaged BRG with a 10-mm-diameter resonator demonstrates an angle random walk of 0.00016 deg/sqrt(hr) and a short-term in-run bias stability of 0.00138 deg/hr. The performance of the BRG is the best among MEMS gyroscopes reported to date.