The phrase "worth its weight in gold" is an idiom that refers to something of great value. However, there are many synonyms that can be used in place of "gold". For example, you might say that something is worth its weight in silver, platinum, or diamonds. Alternatively, you could use other symbolic, non-monetary units of measurement, such as "worth its weight in pearls" or "worth its weight in rubies". The phrase could also be more direct and say "worth a fortune", "priceless" or "invaluable". Regardless of the synonym used, the meaning of the phrase remains the same: something of high value and importance.