A geode,(I bielive)
Quartz is a mineral, not a rock.
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz.
Clastic sedimentary rocks are made of broken pieces of preexisting rock that are compacted together. The mineral quartz makes up sixty percent of the clastic sedimentary rocks.
Sedimentary rock varies greatly in mineral composition. For instance, sandstone is largely quartz; limestone is largely calcite; and claystone is largely clay minerals.
Flint is a hard rock that produces a spark when struck against steel. Flint is a sedimentary rock that is formed from a crypto crystalline quartz.
They are called geodes.
They're geodes.
Geodes
Clasts Pebbles (in a conglomerate) Geodes
Geodes. They can be found in some igneous rocks as well. They start as a hollow cavity created by a gas bubble or decaying organism. Mineral rich water seeps into the cavity and crystals form from the outside toward the inside.
Quartz is a mineral not a rock. Fossils can be found associated with quartz in sedimentary rock not inside the quartz.
Quartz is a mineral, not a rock.
quartz is a mineral, not a rock, so it can't be igneous, sedimentary or metamorphic
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz.
Onyx is a variety of quartz, usually with a sedimentary origin.
The mineral quartz is abundant in sedimentary rocks because quartz is very durable and resistant to chemical weathering.
quartz is a basic mineral and can be in any type of rock