What are some uses of limestone

limestone

Author: Torsten Purle (steine-und-minerale.de) | Last updated: 02/26/2021


Limestone - properties, formation and use

english: limestone | French: calcaire




The decisive factor for the name limestone is the composition of the rock.



Properties of limestones

Definition of limestone: Limestone is a dendritic sedimentary rock of marine (= in the sea) origin.

Various mineral and organic admixtures are what make the actually white ones Limestone in numerous colors appear.
Hematite, for example, has a reddish color, while chlorite and glauconite make limestone appear greener.
The The color of pure, unadulterated limestone is white and becomes yellowish-brown due to the presence of siderite and limonite in the rock, or gets a dark gray to black color due to coal and bitumen.

Limestone is one of the most popular because of its composition monomineral rocks counted, the majority of the mixture parts (= minerals that make up a rock) are dominated by one type of mineral. In the case of limestone, up to 95% of it is either calcite or aragonite - two minerals containing calcium carbonate. Dolomite, feldspars, clay minerals, siderite, quartz or minerals of the mica group occur as secondary parts.

The structure of limestone is rich in pores, oolithic (e.g. roe stone), shell-like, crystalline or compact with fine to coarse grain size.

The density of limestone is 2.70 to 2.90 g / cm³ with a rock hardness of 3 on the Mohs scale.



Formation and distribution of limestone

Limestone is a relic of floods that go back far into the history of the earth and the organisms that live in them. Those organisms - calcareous algae, crustacea (crustaceans), molluscs, brachiopods, foraminifera and corals - provided the starting material for the formation of limestone after their death or through excretions in the period between 145.5 and 65.5 million years ago. Even today, remains of the organisms mentioned can still be found in the limestone as fossils. The limestone layers were drained and compacted under the weight of the overlying layers and the silting up of the sea of ​​chalk at that time.

Additionally contained minerals such as calcite, dolomite or gypsum also caused the stable cementing of the former loose material.

Limestone, which was declared Rock of the Year 2010 by the Professional Association of German Geoscientists (BDG e.V.), is a widespread rock. The proportion of limestone in the global occurrence of all sedimentary rocks is 10%.
Part of the Alps / Europe is built entirely from the rock, recognizable by the name Limestone Alps.

There are also other limestone deposits in Sweden; Denmark; French Jura / France; England; Belgium; Black Forest, Swabian Alb, Stuttgart (Baden-Württemberg), Franconian Alb (Bavaria, so-called Jura limestone or Jura marble), Hunsrück, Eifel, Westphalia, Weser Uplands, Ore Mountains, Thuringian Basin, Rüdersdorf (Brandenburg) / Germany; Greece; Italy; Croatia; Serbia; Ghana; Tunisia; Vietnam; China; Iran; Iraq; Turkey; Japan and the USA, where the world's largest limestone deposits are located in the US state of Michigan.


Limestone and marble

Marble and limestone are sometimes compared and / or confused with one another.
Except for the color and the mineral composition, both rocks have little in common.

The essential difference between limestone and marble is the Emergence. While limestone is a sedimentary or deposit rock, marble is a rock of metamorphic origin. Metamorphites are rocks that result from transformation under high pressure and / or temperature conditions from other rocks. In the case of marble, the parent rock can very well be limestone, but also other calcareous rocks. In the course of regional or contact metamorphosis, e.g. During ore formation, tectonic activity or as a result of rising magma, the mineral composition of the original rock can be changed, just like the structure of the rock.


Importance and use of limestone

Already in ancient Egypt people made use of natural stone and built the pyramids of Giza from limestone.
Nowadays limestone is used for the production of tiles, worktops, facade and wall cladding (sometimes under the misleading trade name antique marble) or as crushed stone, paving stone and chippings. Limestone is also important for the production of cement, glass, for paint and as a polishing element in toothpastes.
Limestone is only conditionally recommended as a building material for outdoor use, insofar as acid rain and smoke gases in the air add to the natural stone. A famous example in which limestone was used as a building material is the Washington Monument in Washington / USA.
The use of limestone as a material for the manufacture of stone paper is comparatively new. The sedimentary rock is finely ground, mixed with polyethylene resin and processed into paper. Stone paper is just as suitable for writing as ordinary paper, but has, among other things, water resistance. In addition, water and the resource wood are dispensed with during production.


Evidence of limestone

Limestone can be examined for authenticity with diluted hydrochloric acid - limestone dissolves on the surface with the development of foam.


Also interesting:
⇒ Stone paper: writing on limestone
⇒ Constant dripping wears away the stone
⇒ cycle of rocks


Swell:
⇒ Pellant, C. (1994): Stones and Minerals. Ravensburger nature guide. Ravensburger Buchverlag Otto Maier GmbH
⇒ Schumann, W. (1991): Minerals rocks - characteristics, occurrence and use. FSVO nature guide. BLV Verlagsgesellschaft mbH Munich
⇒ Maresch, W., Medenbach, O .; Trochim, H.-D. (1987): The colored natural guide rocks. Mosaik Verlag GmbH Munich *
⇒ Murawski, H. (1992): Geological Dictionary. Ferdinand Enke Verlag Stuttgart
⇒ Schumann, W. (1994): Collecting stones and minerals; find, prepare, determine. BLV Verlag Munich