“I know their are different types of gold, like 14 carrots and 18 carrots and stuff but whats the difference and what is the other stuff they use if theres less carrots of gold and is 9 carrots like half gold and half something else?”
Fine gold (gold which is 99.9% gold) is 24 carats. It is extremely unusual to find jewelery which is made from 24k gold as it is a very soft material, entirely unsuitable to shaping into solid jewelry. All other carats of gold are essentially measurements in fractions of 24. Therefore 18 carat gold is 18/24ths gold (75%), 14 carat gold jewelery is 14/24ths gold (58.5%) and 9carat gold is 9/24ths gold (37.5% gold).
The other metal which gold jewelery contains is normally copper. This makes the gold harder and more able to keep its shape.