* Geodes: These are spherical or egg-shaped cavities in rocks that are lined with crystals. They are often found in volcanic rocks, limestone, and other sedimentary rocks.
* Vugs: These are small, irregular cavities in rocks that can be filled with crystals. They are often found in igneous and metamorphic rocks.
* Druses: These are clusters of crystals that have grown on the surface of a rock. They are often found in geodes, vugs, and other cavities.
* Veins: These are narrow, linear openings in rocks that can be filled with crystals. They are often found in metamorphic rocks and can be very large, even extending for miles.
* Pegmatites: These are igneous rocks that are very coarse-grained and often contain large crystals. They are often found near granite intrusions.
It's important to note that not all rock formations that contain crystals are created equal. Some are more likely to be filled with large, high-quality crystals than others. Geodes, for example, are often prized for their beautiful crystals.
