Answer:
What is neither inside the house nor outside the house but a necessity for any home?
What is the only letter in the alphabet that does not appear anywhere on the periodic table of elements?
What can be measured but not seen?
A precious stone, as clear as diamond. Seek it out while the sun's near the horizon. Though you can walk on water with its power, try to keep it, and it'll vanish in an hour.
More precious than gold, but cannot be bought, Can never be sold, only earned if itβs sought, If it is broken it can still be mended, At birth it canβt start nor by death is it ended.
Iβm grown from darkness but shine with a pale light. Very round I am and always a lady's delight.