This image has currency in it to indicate scale. Using coins for scale is discouraged as it will require people unfamiliar with them to look up the dimensions or guess, both of which defeat the purpose of the object in the first place. Coins can also reinforce a geographical bias, and some coins' designs are copyrighted. Ideally, a photograph should include a ruler with the subject (example) or an added scale marking. SI ("metric") units are the most commonly used worldwide (see meter and centimeter). Images with coins to indicate scale Common coin diameters for reference: U.S. dollar (as of?): 1¢: 19.05 mm, 0.75 in 5¢: 21.21 mm, 0.84 in 10¢: 17.91 mm, 0.71 in 25¢: 24.26 mm, 0.94 in 50¢: 30.61 mm, 1.22 in $1: 26.5 mm, 1.02 in Canadian dollar (as of?): 1¢: 19.05 mm, 0.75 in 5¢: 21.2 mm, 0.83 in 10¢: 18.03 mm, 0.71 in 25¢: 23.88 mm, 0.94 in 50¢: 27.13 mm, 1.07 in $1: 26.5 mm, 1.02 in $2: 28 mm, 1.1 in Pound sterling as of 2021: 1p: 20.32 mm, 0.8 in 2p: 25.91 mm, 1.02 in 5p: 18 mm, 0.71 in 10p: 24.5 mm, 0.96 in 20p: 21.4 mm, 0.84 in 50p: 27.3 mm, 1.07 in £1: 23.03–23.43 mm, 0.91–0.92 in £2: 28.4 mm, 1.12 in Euro as of 2002: 1c: 16.25 mm, 0.64 in 2c: 18.75 mm, 0.74 in 5c: 21.25 mm, 0.84 in 10c: 19.75 mm, 0.78 in 20c: 22.25 mm, 0.88 in 50c: 24.25 mm, 0.95 in €1: 23.25 mm, 0.92 in €2: 25.75 mm, 1.01 in Deutsch ∙ English ∙ español ∙ français ∙ Gaeilge ∙ italiano ∙ Plattdüütsch ∙ português ∙ sicilianu ∙ svenska ∙ suomi ∙ македонски ∙ русский ∙ മലയാളം ∙ 한국어 ∙ 日本語 ∙ 中文 ∙ 中文（简体）‎ ∙ עברית ∙ +/−

	This work is in the public domain in the United States because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code. Note: This only applies to original works of the Federal Government and not to the work of any individual U.S. state, territory, commonwealth, county, municipality, or any other subdivision. This template also does not apply to postage stamp designs published by the United States Postal Service since 1978. (See § 313.6(C)(1) of Compendium of U.S. Copyright Office Practices). It also does not apply to certain US coins; see The US Mint Terms of Use.
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• 2006-10-24 02:23 Easchiff 600×451×8 (51819 bytes) Image of trona, a naturally occurring mineral that is primarily hydrated sodium bicarbonate carbonate (Na₃H(CO₃)₂·2H₂O). Image from: http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials/sodaa
• 2006-10-24 02:05 Easchiff 360×271×8 (21427 bytes) Image on trona, a naturally occurring mineral that is primarily hydrated sodium bicarbonate carbonate (Na3HCO3CO3·2H2O). Image from: http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials/sodaash.html Photographer unknown.