Glass Gem with a crack

Broken things are all in the world
every person has once has heard.
But cracks are different then they seem,
half way broken like a dream.
Cracks are fixable in many ways,
though it might take years or days.
Glass cracks a lot of time
and cost more than just a dime.
Gems are worth much more
but the age is higher in the core.
A Glass gem breaks quickly and fast
and is rarely fixed. The damage is too last.