Hi Peter, these three rocks that you asked about are all igneous rocks that form from volcanic magma. The reason that pumice and scoria have holes in the rock and granite does not is due to the way they form. This rock is a piece of granite, which is an intrusive igneous rock..
Furthermore, what causes rocks to have holes in them?
A fine grained rock is formed as a result of faster cooling, which can occur near the surface of the earth. Natural processes of decay, weathering and erosion, cause these trapped minerals to decay faster than the surrounding rock, making 'holes' in them, which many times are semi-circular to circular.
One may also ask, do sedimentary rocks have holes? Sandstone rocks with holes are known as porous sandstones. The porosity is formed when spaces are left during the cementation process. The cementation process is when a liquid form of a mineral such as calcite or quartz “glues” the sand grains together. The holes that are left are great places for storing water or oil.
Similarly, what kind of rocks have holes in them?
Igneous rocks like pumice have holes because the maga/lava cools quickly, trapping air and gas bubbles inside.
Where are hag stones found?
An adder stone is a type of stone, usually glassy, with a naturally occurring hole through it. Such stones have been discovered by archaeologists in both Britain and Egypt. Commonly, they are found in Northern Germany at the coasts of the North and Baltic Seas.
Related Question Answers
Where do intrusive rocks form?
Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet. When lava comes out of a volcano and solidifies into extrusive igneous rock, also called volcanic, the rock cools very quickly.What are the holes in igneous rocks called?
When this happens gasses dissolved in the magma are able to come out of solution, forming gas bubbles (the cavities) inside it. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas bubbles and traps them inside, preserving them as holes filled with gas called vesicles.What kind of rocks are geodes?
Geodes (derived from the Greek word "γεώδης" meaning "Earth-like") are geological secondary formations within sedimentary and volcanic rocks. Geodes are hollow, vaguely circular rocks, in which masses of mineral matter (which may include crystals) are secluded.What are pocket rocks?
Pocket Rocks and Comfort Stones for Children. Give them a POCKET ROCK, a token to carry in their bag or pocket throughout the day!How do sedimentary rocks form?
Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension. This sediment is often formed when weathering and erosion break down a rock into loose material in a source area.Is scoria a sedimentary?
Scoria is a highly vesicular, dark colored volcanic rock that may or may not contain crystals (phenocrysts). It is typically dark in color (generally dark brown, black or purplish red), and basaltic or andesitic in composition. Most scoria is composed of glassy fragments, and may contain phenocrysts.What are ocean rocks made of?
The crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.What kind of rock is gneiss?
metamorphic
How do you identify gneiss?
Gneisses have minerals large enough to be identified with the naked eye that have been segregated into roughly parallel bands or layers. These bands may be straight or tightly folded. Many gneisses are made of the same minerals as coarse-grained intrusive rocks such as granite or diorite.What rocks are red?
The red color of some of the outcrops of the Aztec Sandstone is due to presence of iron oxide or hematite. Exposure to the elements caused iron minerals to oxidize or “rust,” resulting in red, orange, and brown-colored rocks.Do igneous rocks have crystals?
Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidified: magma that cools slowly will form an igneous rock with large crystals. lava that cools quickly will form an igneous rock with small crystals.What type of rock is shale?
sedimentary rocks
What type of rock is marble?
metamorphic rock
What type of rock contains rounded grains?
Sedimentary rocks contain rounded grains in layers. The oldest layers are at the bottom and the youngest layers are at the top. Sedimentary rocks may contain fossils of animals and plants trapped in the sediments as the rock was formed.How is obsidian formed?
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. The inhibition of atomic diffusion through this highly viscous lava explains the lack of crystal growth.Is sandstone a sedimentary rock?
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) mineral particles or rock fragments.What is in a metamorphic rock?
A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.What is a rock scientific definition?
A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. Rocks are usually grouped into three main groups: igneous rocks, metamorphic rocks and sedimentary rocks.What causes honeycomb weathering?
Cause. Many explanations have been proposed for honeycomb and other cavernous weathering. Currently, it is considered to be polygenetic in origin; being the result of complex interaction of physical and chemical weathering processes, which include salt weathering and cyclic wetting and drying. 
