Rock on! Indiana limestone: NIST's first and latest SRM
It may sound like sentimentality, but it's coldly practical--the National Institute of Standards and Technology (NIST) has reissued one of its earliest Standard Reference Materials (SRMs), a mineral sample first distributed in 1910. Issue "d" of SRM 1 consists of a 70-gram sample of argillaceous ("containing clay") limestone quarried in Putnam County, Ind. NIST certifies each sample for concentrations of 12 major chemical constituents and offers "informational" values for 32 other constituents and properties.
Standard Reference Materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes well over a thousand different materials that are used throughout the world to check the accuracy of instruments and test procedures.
They range from industrial materials like SRM 1 or SRM 2172 ("S-7 Tool Steel") to samples used in clinical chemistry (SRM 1951b--Lipids in Frozen Human Serum, SRM 2390--DNA Profiling Standard), environmental monitoring (SRM 1649--Urban Dust, SRM 1641--Mercury in Water), electronics (SRM 476--Linewidth Measurement, SRM 2543--Silicon Resistivity) criminal forensics (SRM 2379--Drugs of Abuse in Human Hair, SRM 2285--Arson Test Mixture), and dozens of others. About 350 SRMs support the auto industry, for example, from manufacture of sheet metal, windshields, tires, and transmission gears to final assembly and subsequent operation.
Prosaic limestone is a critical natural resource. In addition to being a building material, it is used in the manufacture of lime for agricultural and chemical processes, cement and concrete, and iron and steel. NIST researchers worked with the U.S. Geological Survey and six commercial laboratories in the mining, minerals, construction and analytical services sectors in the United States and Canada to produce SRM 1d. Details about SRM 1 and hundreds of other NIST Standard Reference Materials can be found at www.nist.gov/srm.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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