Limestone

| Mineral List | Rock List | Guidelines for Rock Collections |

Rock class: Sedimentary Rock
Composition: CaCO3
Hardness: 3-4
Luster: dull
Color: white, grey, black when combined with organic material
Fracture: very dense varieties break with a conchoidal fracture
Grain: very fine
Environment: Deposited on seafloor from skeletons of coral and sea shells (like chalk). Often contains fossils. Oolitic limestone imitates an organic appearance (looks almost like little eggs), but is actually a chemical precipitate.
Uses: Mortar, steel-smelting, concrete aggregates. Often seen in buildings (e.g., Great Pyramids of Egypt). Are any buildings on campus made of limestone? How do you know? Where was it obtained?
Comments: Dissolved by acids in water to produce subterranean caverns and their formations. Springs derived from caves often contaminated, impure. Water percolated through limestone contains lime and is therefore Òhard.Ó Streams in limestone areas are clean-bottomed, without silt. [limestoneGlacialStriations.jpg]

Rock class:	Sedimentary Rock
Composition:	CaCO3
Hardness:	3-4
Luster:	dull
Color:	white, grey, black when combined with organic material
Fracture:	very dense varieties break with a conchoidal fracture
Grain:	very fine
Environment:	Deposited on seafloor from skeletons of coral and sea shells (like chalk). Often contains fossils. Oolitic limestone imitates an organic appearance (looks almost like little eggs), but is actually a chemical precipitate.
Uses:	Mortar, steel-smelting, concrete aggregates. Often seen in buildings (e.g., Great Pyramids of Egypt). Are any buildings on campus made of limestone? How do you know? Where was it obtained?
Comments:	Dissolved by acids in water to produce subterranean caverns and their formations. Springs derived from caves often contaminated, impure. Water percolated through limestone contains lime and is therefore Òhard.Ó Streams in limestone areas are clean-bottomed, without silt.