Image:Cobalt OreUSGOV.jpg

From Wikipedia, the free encyclopedia

Wikimedia Commons logo This is a file from the Wikimedia Commons. The description on its description page there is shown below.
Commons is a freely licensed media file repository. You can help.

Cobalt ore

U.S. quarter

This image has currency in it to indicate scale.

Avoid using objects such as coins for scale, as they 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 are particularly bad as they can reinforce a geographical bias, and some coins' designs are not free content.

Ideally, a photograph should include a ruler with the subject (as seen in this photo) or add a scale marking via an image editor instead (as seen in this photo). SI/metric units are the most commonly used worldwide (see metre, 1 E-2 m).

Examples of bad practice: here.

A tape measure


Common coin diameters for reference:

  • U.S. dollar:
  • Canadian dollar:
  • Pound sterling
  • Euro

Deutsch | English | Italiano | +/-


Source: http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/photogallery/ ; English Wikipedia, original upload 3 August 2004 by Chris 73

Public domain This image is a work of the "Minerals in Your World" project, a cooperative effort between the United States Geological Survey and the Mineral Information Institute. The images were featured in the "Minerals and Materials Photo Gallery" on the website of the U.S House Subcommittee on Energy and Natural Resources. As a work of the U.S. federal government, the image is in the public domain.

File history

Click on a date/time to view the file as it appeared at that time.

Date/Time Dimensions User Comment
current 05:45, 14 September 2005 600×450 (79 KB) Saperaud (Cobalt ore Source: Cobalt, Ores {{PD-USGov-Interior-USGS-Minerals}} Category:http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/photogallery/ ; English Wikipedia[[Category:original upload 3 August 2004 by [[:en:User:Chris 73|Chris 73)
The following pages on Schools Wikipedia link to this image (list may be incomplete):
The 2008 Wikipedia for Schools has a sponsor: SOS Children , and is a hand-chosen selection of article versions from the English Wikipedia edited only by deletion (see www.wikipedia.org for details of authors and sources). See also our Disclaimer.