What does a solid, 1 mile diameter subterranean glass sphere look like?

There is a solid glass sphere that is 1 mile in diameter. It is completely covered in dirt and rock, except for one small room that is built adjacent to the sphere. One of the four walls of this room is the surface of the sphere. What would the sphere look like to someone standing in this room holding a pitch torch?

I understand the answer might depend on what type of glass the sphere is made of. Please feel free to assume whatever type of glass makes answering this question easiest. The sphere can even be diamond, or any other "clear" mineral, if using glass is a problem.

EDIT1: Assume a very fine polished surface.

EDIT2: It seems I have to clarify. When I ask "what would the the sphere look like", I want to know what a person looking at the surface of the sphere would see. Unless 1 mile wide blocks of glass cause blindness, "nothing" is not an answer. I want to know, very literally, what looking into this sphere would be like. If the glass is completely dark, please elaborate: is it dark like a gloomy room behind a glass panel, or is the surface of the glass completely black as if made of obsidian? Would bringing the source of light closer to the surface of the glass have any effect?

posted over 6 years ago

Pink Sweetener‭

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