24K gold is called fine gold, which is 99.99 or 99,95 gold ( there is no 100% gold till now ).
18K gold means 75% (18/24) fine gold;
14K gold means 58% (14/24) fine gold.
All of jewelry setted with stones are made with 18K or 14K gold;
24k gold could not be used due to it is too soft to hold stones.
White gold is usually 75% gold, 16% palladium and 9% silver.
You may also see rose, blue, grey or green gold that have other metals blended with gold.
What is white gold?
White gold is an alloy of yellow gold and at least one white metal, usually nickel or palladium. Because 18K white gold is 75% gold, and 14K white gold is 58.3% gold, jewelry made from these metals has a slight yellow color. To enhance the whiteness, almost all white gold is plated with rhodium, a shiny, white metal which is extremely hard. Depending on the amount of wear to a piece of jewelry, over time this rhodium plating may wear off, revealing the original metal color.
What is rose gold?
Rose gold is a gold and copper alloy. A common alloy for rose gold is 75% gold and 25% copper, making up 18 karat rose gold. There is no “pure” rose gold, since it is an alloy of gold and copper. The more copper, the stronger the “rose” color.
What is vermeil?
Vermeil is essentially .925 sterling silver layered with gold. While standard plating is about 2 millionths of an inch of gold, a vermeil coating is 50 times that thickness, or 100 millionths of an inch over sterling silver. What you get with vermeil is gold jewelry with the exact same shine and richness of real 14 karat gold that won't wear down easily. To care for your gold vermeil jewelry, simply polish with a cloth, and never machine polish or use any chemicals such as silver or gold cleaner.