I found this rock while hiking down into a canyon near Abiquiu, New Mexico. There were a few others like it nearby. It is creamy white on the outside, and a translucent, bluish gray color on the inside. It was fairly smooth both inside and out.
ADDITIONAL INFORMATION: I left the rock where I found it, and am no longer in the area, but I will do my best to describe it according to the guidelines. 1. I did not have to dig to find this rock. It was lying on top of the soil among other rocks. There were others nearby, mostly smaller than this one. 2. Size: This particular piece of rock was about the size of a golf ball. 3. The white so prevalent on one side seemed fused into the gray-blue color in the "middle" of the rock. The creamy white color was opaque, but the blue-gray color had a slight transparency to it. The color of the outside seemed marbled into the middle. Some of the white had some rough darker cream patches on it. 4. I did not scratch it. The texture felt very smooth in places, like glass. In other places, it felt like sandpaper (where the darker cream patches were.) 5. It seemed a normal weight; not unusually or surprisingly heavy or light for its size. 6. I will include an additional picture of the surroundings where I picked the rock up. It was a steep, rocky terrain. We were hiking down into a canyon in New Mexico near the Rio Puerco, very close to Lake Abiquiu.