First up are Agates, which actually are a member of the Chalcedony family of gemstones. Gemstones are kind of like animal classifications. There are groups, and subgroups, for each gemstone. It can get confusing. If I have a jewelry piece created, I will share it, or an image of a loose stone. If not I will try to find a video. I love my Gemstones of the World book, and I really need an updated version.
Agates are very common gemstones, found world wide, and are often made into beautiful carvings. It is very often banded, with curved bands, a distinguishing identifier from other Chalcedony. They have a hardness of 6.5-7, which means you need to be a little gentle with them, when placing in jewelry, and then wearing. Agates are also often died, due their porous make up, and they come in some of the most beautiful colors, vivid and bright. Agates are found close to where volcanic masses are, and if you get to see petrified agates, that is an awesome process where the agate replaces the petrified wood. Very cool! There are varieties of Agates, but most will have the agate name to it. Like, Dendritic Agate, Crazy Lace Agate, Blue Lace Agate, Fire Agate, etc.
Below are a couple of videos about Agates. The first one is how to identify Agates, and these are in their rough form, which means no cutting or polishing has taken place.