Answer:
Each morning I appear to lie at your feet, all day I follow no matter how fast you run. Yet I nearly perish in the midday sun.
A house of wood in a hidden place. Built without nails or glue. High above the earthen ground It holds pale gems of blue.
The more of it there is, the less you see.
It stands upright and can be quite grand. Its secret is not hidden but right at hand. What is it?
Sleeping during the day, I hide away. Watchful through the night, I open at dawn's light. But only for the briefest time, do I shine. And then I hide away. And sleep through the day.
I am your mother's brother's only brother in law. Who am I?