worth one's weight in gold

Etymology
Because gold is expensive even in small amounts.

Adjective

 * 1)  Very valuable.
 * 2) * 2011, "Summer (Where Do We Begin?)" (song), 
 * Summer, every single moment is worth its weight in gold
 * Summer, it's like the world's best story and it's waiting to be told
 * Summer, it's like the world's best story and it's waiting to be told

Translations

 * Finnish: painonsa arvoinen kultaa
 * French:
 * Polish:
 * Russian:
 * Swedish: värd sin vikt i guld