Calcite | EPFL Graph Search

Are you an EPFL student looking for a semester project?

Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German Calcit, a term from the 19th century that came from the Latin word for lime, calx (genitive calcis) with the suffix -ite used to name minerals. It is thus a doublet of the word chalk. When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is reserved for a variet

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (41)

Related publications

Related people (5)

Related people

Related units (4)

Related units

Related concepts (89)

Related concepts

Related courses (20)

Related courses

Related lectures (33)

Related lectures

ENV-406: Biomineralization: from nature to application

Understanding process and role of biomineralization (minerals formed by living organisms) in context of Earth's evolution,global chemical cycles, climatic changes and remediation.

CH-314: Structural analysis

The aim of this course is to treat three of the major techniques for structural characterization of molecules: mass spectrometry, NMR, and X-ray techniques.

PHYS-206: Physics IV

Wave physics, Introduction to quantum mechanics.

The grinding tip of the sea urchin tooth exhibits exquisite control over calcite crystal orientation and Mg distribution

Anders Meibom

The sea urchin tooth is a remarkable grinding tool. Even though the tooth is composed almost entirely of calcite, it is used to grind holes into a rocky substrate itself often composed of calcite. Here, we use 3 complementary high-resolution tools to probe aspects of the structure of the grinding tip: X-ray photoelectron emission spectromicroscopy (X-PEEM), X-ray microdiffraction, and NanoSIMS. We confirm that the needles and plates are aligned and show here that even the high Mg polycrystalline matrix constituents are aligned with the other 2 structural elements when imaged at 20-nm resolution. Furthermore, we show that the entire tooth is composed of 2 cooriented polycrystalline blocks that differ in their orientations by only a few degrees. A unique feature of the grinding tip is that the structural elements from each coaligned block interdigitate. This interdigitation may influence the fracture process by creating a corrugated grinding surface. We also show that the overall Mg content of the tooth structural elements increases toward the grinding tip. This probably contributes to the increasing hardness of the tooth from the periphery to the tip. Clearly the formation of the tooth, and the tooth tip in particular, is amazingly well controlled. The improved understanding of these structural features could lead to the design of better mechanical grinding and cutting tools.

2009

Covalent attachment of proteins to calcite surface for the single molecule experiments

Two protocols of covalent attachment of proteins onto the calcite surface, viz. one using the metallochelat and second using the aminohexil, are elaborated. Single molecule force spectroscopy method has been used to test their efficiency and practical applicability. Experiments were performed measuring the specific interaction force between bovine serum albumin (BSA) fixed onto the freshly cleaved calcite single crystal surface (procedure under the study here) and its polyclonal antibody (Ab-BSA) immobilized onto an AFM tip using standard and well studied procedure. We found the conditions, when up to 3-3.5% of tip-sample approaches lead to the formation of a single specific bond. (C) 2007 Elsevier B.V. All rights reserved.

2008

A Reassessment of of the geochemical and isotopic fidelity of biogenic carbonates

Arthur Adams, Deyanira Graciela Cisneros Lazaro, Jinming Guo, Anders Meibom, Jaroslaw Hubert Stolarski, Tarek Axel Vennemann

Oxygen isotope compositions of calcite foraminifera tests are considered to be a robust palaeotemperature proxy at earth-surface conditions, where diffusion is slow. Recrystallization of tests during diagenesis may be optically identified and is often the basis for excluding such samples from paleotemperature calculations e.g. “glassy” vs. “frosty” foraminifera. However, biogenic and abiogenic calcite can isotopically reequilibrate and recrystallize in calcite-saturated fluids, even at low temperatures (

2019

Calcium carbonate

Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, ga

Limestone

Limestone (calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different c

Aragonite

Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physi