one or two of those things provided are igneous rocks.
133196
Porphyry & Basalt are both igneous.\n\nPorphyry is an intrusive igneous rock w/ different crystal sizes.\n\nPorphrytic is a texture term that is often used to describe certain types of igneous rocks having two distinct crystal sizes. The large crystals inside the rock are called phenocrysts. Porphyrtic granite is an example. I tell students that it reminds me of a chocolate chip cookie w/ the large crystals representing the chocolate chips. That usually helps them to get it.\n\nBasalt is an extrusive igneous rock composed mainly of darker minerals such as magnesium.\n\nLimestone is a sedimentary rock as is shale.
461159
the first could be either Flourite (4), Apatite (5) or Orthoclase (6).  The second could be either Topaz (8) or Corundum (9).
282763
below the crust, above the core.
303056
I have to admit im not too clued up on the geology of Maryland, however over here in the UK we have in the Mendip Hills something which resembles Obsidian but in fact its not. On a university field trip we went to an old smelt, where the guys used to smelt Limestone and the result was this black shiny stuff that looked identical to Obsidian. The stuff was strewn all over the place in big heaps. Confused the 'ell out of us students initially until we were told the what it actually was. I wish I could remember more about it but then again uni was a bit of a blur!
442464
My guess is dissipation, hydrothermal, volcanic. Just guessing.
19822
heres a sweet little find in franklin n.j. they have stone that glows foresent when exposed to blacklight
609929
the simplest explanation is as follows:\n\n* igneous rocks are formed when molten lava is erupted on to the earth's surface and cools. i.e. basalt lavas. \n\n* sedimentary rocks are formed when other rocks (possibly igneous, metamorphic or previous sediemtnary rocks) are eroded chemically or physically and are then redeposited. i.e. sandstones and mud stones.\n\n* metamorphic rocks are formed when other rocks (igneous or sedimentary typically) are buried and then exposed to high temperatures and pressures that change the properties of that rock. i.e. marble - metamorphosed limestone.
642920
you found a meteorite.
13821
Third Day. I like a lot of rock.
6427
There are a number of options
232962
They are also soft metals.  Easy to mine, easy to smelt.
167332
Not the full 100% it will be mixed or another fuel source will be found.
199767
Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This magma can be derived from either the Earth's mantle or pre-existing rocks made molten by extreme temperature and pressure changes. Over 700 types of igneous rocks have been described, most of them formed beneath the surface of the Earth's crust. The word "igneous" is derived from the Latin ignis, meaning "fire".
674514
its some type of energy thing for some
665157
2 mostly but a combination of the three if possible
35983
Here are some intresting ones.
441682
I think volcanic exhalatives formed from molten material rocks under great heat and pressure.