Geoculus are the second type of Oculi in Genshin Impact. These important resources can be used to rank up the Statues of the Seven, netting you some pretty important buffs and benefits to your stats.
Geoculus can be found in the Liyue region of the game, and they can be used to rank up Statues of the Seven that are found in the same region. While it is certainly not essential to find them all to get a powerful party, the benefits from ranking up Statues of the Seven are certainly worthwhile, as it is one of the ways that you can increase your Stamina.
Geoculus will appear in the world as large golden objects that float in the air and look like very ornate crystals. Just like the other Oculi, they will range from being very easy to get, and very difficult to get, often involving some climbing and gliding to get to.
The above map will show you exactly where they all are, using the wonderful Genshin Impact Interactive Map. You can use the interactive map to zoom in and get a better view of exactly where each one is, although they are quite common in the Liyue region, and not really that hard to track down thanks to the minimap. When you are close to them, they will be marked on the minimap by a small six-pointed star icon, so they are actually very hard to miss once you know their general location.