There are just a few things I want to mention regarding gemstones and pearls for purchase. try to find genuine gemstones, and if possible, get those which have not had enhancements made by heating or irradiation. Natural gemstones, although difficult to find nowadays, are always the best value. even if hey are flowed rather than perfect, they may not look as faine and fancy as those which have had color enrichment, but those small flaws indicate they are the genuine article.
Always get the highest carat weight you can when investing; anything over 5 carats is best though in very rare gems this may be difficult to obtain and will be pricey when you get them. Remember also, that gems mined from the earth (rather than created synthetically, i.e., man-made) are one day going to be depleted, for there are only a certain number of gems and minerals IN the earth, so once the supply is exhausted, the gems will become more valuable.
As for Pearls, saltwater pearls are of more value than freshwater pearls for they are more difficult to obtain. AAA pearls usually have very fine luster and lovely color; there are many shapes and sizes of pearls for they are created by something which irritates the body of the animal and it exudes a coating over it to prevent it from being so abrasive - the more coats it has, the larger the pearl becomes. The best quality AAA pearls have glossy luster with a subtle overplay of heightened natural color and are usually 7-8mm or above in size.
The most favored shape is round but there are baroque (a natural shape slightly off-round), flattened round pearls called coin pearls, as well as many other shapes, elongated, pear, and other shapes are also beautiful and if they have high luster and nice color, they can be exquisite. Pearls come in every color of the rainbow, but most have been enhanced if the color is other than a natural black/peacock, gray, or white, off-white, or pastel. The colors such as lavender, blue, or green are artificially enhanced but can add to jewelry designs so they have their place in jewelry.
There is a lot more - will try to add more later. Happy hunting!