Rocks

In Animal Crossing there are several rocks in the town, normally in each there is a maximum of 7 rocks. These rocks can serve two things; Gather Berries, catch a Mealybug or Centipede (Animal Crossing: City Folk / Let's Go To The City only).

Beginning with Animal Crossing: New Leaf, a rock can appear spontaneously overnight. In this case, it is a mineral. To remove it, simply hit the rock with the shovel and it will be destroyed, exposing the mineral. In New Horizons if you eat fruit you can break the rocks, they will reappear in a different place the next day, if you break several rocks only one rock will appear per day that passes, so you have to take that into account before breaking many. Also if you hit them you can get materials to make DIY recipes.

Berries

Hitting with the Shovel or an Ax (but the shovel is recommended since the ax breaks) to a rock you can get a maximum of 8 bags of Berries; 100, 300, 400, 800, 1.000, 2.000, 4.000 and 8.000 Berries in total although if one misses a blow the total can be reduced, the faster it is hit with the Shovel (or Ax) the more it will come out, and if a silver shovel it is possible that when the player hits the rock a sharp noise will be heard, which will make the bag or coin that comes out at that moment have double the normal value, for example, if when you take out a bag of 2.000 hey the noise this happens to have 4.000 berries, thus increasing the total value of the berries that the rock had.
In Animal Crossing (population: increasing!) He gives you three bags of 100, three of 1.000 and one of 10.000, for a total of 13.300 Berries.
Also, in Animal Crossing: New Leaf, you can get 8 minerals randomly instead of money with the Silver Shovel (only rarely, not constantly).

Many neighbors will comment that they once heard rumors about rocks giving berries if you hit them with the shovel. Although there is only one rock that gives berries per day (and it is always different) if you already get as much berries as possible you will not be able to get more until the next day.