Answer:
.999 = 24 carat = 99.9%
.916 = 22 carat = 91.6%
.750 = 18 carat = 75%
.585 = 14 carat = 58%
.375 = 9 carat = 37.5%
A gold item listed as .575 is 57.5% pure gold.
Its worked out thus:
24 carat gold is pure gold..
Therefore
.575 or 57.5% = 13.8 carat gold. Its real gold - not gold plated.