The difference is genuine means it is a mined, natural gemstone from the earth. Created, simulated, faux and other descriptions mean they are man made but not necessarily less in quality but usually cheaper in price. It is very common to find created gemstones in gold jewelry now.
OK, because one of my friends told me that created meant that it looked the same but it was really glass or plastic that they colored and cut and did other things to to make it look that way