Japanese Cultured Pearl Necklace

by Lisa
(morgantown Wv usa)

I was given a Japanese cultured pearl necklace that is at least 20 yrs old but I believe older. I was also told that it cost a ton of money. I want to know the difference between Japanese cultured pearls and regular pearls and do they have any real value. This necklace hasn't been worn but a few times and they are in mint conditions I also have the original case that it in came in 20 yrs + ago. Thank You for any information you can give me . Lisa