Answer:
Lovely and round, I shine with pale light. Grown in the darkness, a lady's delight. What am I?
I'm a precious stone in a pack of cards. What am I?
Break me and I am better, immediately set and harder to be broken again. What am I?
When it comes to me you go on red and stop on green.
What has a thumb and four fingers but is not alive?
The answer I give is yes, but what I mean is no. What was the question?