Found this smooth & polished stone years ago while digging about 3-5 feet down in the backyard in the lower portion of NY. The light area is semi-translucent and can appear white to a very light lavender with a brownish area that is striated. I think it is just so pretty and would love to know what it is. Any ideas? Thank you so much.
Yes. Just like what Michael said, it looks like a form of a polished silica mineral (quartz). Agate would be the most suitable name for that because of the banding and this is the most common form of chalcedony (cryptocrystalline quartz).