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Alexandrite

Tsarstone collectors guide


Negative reading

Negative reading
Testing a gemstone on a refractometer prism, when the stone has a greater refractive index than the measuring prism of the device, or higher than the refractive index of immersion liquid used for optical contact, the scale of refractometer remains dark and the only shadow edge that can be seen is that of immersion liquid, such stones or diamonds give a negative reading.
Bibliographic details
Page title Definition of Negative reading
Author David Weinberg
Website title Alexandrite Tsarstone Collectors Guide
Date published 03 July 2010 04:44 UTC
Date accessed 03 April 2026 18:57 UTC
Permanent link http://m.alexandrite.net/viewpage.html?id=GG-099-00004
AMA style
David Weinberg. "Definition of Negative reading". In Alexandrite Tsarstone Collectors Guide. July 03, 2010, 04:44 UTC. Available at: http://m.alexandrite.net/viewpage.html?id=GG-099-00004. Accessed April 03, 2026.
APA style
"Definition of Negative reading". (2010, July 03). In Alexandrite Tsarstone Collectors Guide. Retrieved 18:57, April 03, 2026, from http://m.alexandrite.net/viewpage.html?id=GG-099-00004.
Bluebook style
"Definition of Negative reading", http://m.alexandrite.net/viewpage.html?id=GG-099-00004 (last visited April 03, 2026).
Bluebook: Harvard JOLT style
See Alexandrite Tsarstone Collectors Guide, "Definition of Negative reading", http://m.alexandrite.net/viewpage.html?id=GG-099-00004 (Testing a gemstone on a refractometer prism, when the stone has a greater refractive index than the measuring prism of the device, or higher than the refractive index of immersion liquid used for optical contact, the scale of refractometer remains dark and the only shadow edge that can be seen is that of immersion liquid, such stones or diamonds give a negative reading.) (as of Apr. 03, 2026, 18:57 GMT).
CBE/CSE style
David Weinberg. "Definition of Negative reading". In Alexandrite Tsarstone Collectors Guide. 2010 Jul 03, 04:44 UTC.[Internet], Alexandrite Tsarstone Collectors Guide; 2010 Jul 03, 04:44 UTC [cited 2026 Apr 03]. Available from: http://m.alexandrite.net/viewpage.html?id=GG-099-00004.
Chicago style
David Weinberg, "Definition of Negative reading", http://m.alexandrite.net/viewpage.html?id=GG-099-00004, (accessed April 03, 2026).
MLA style
"Definition of Negative reading". Alexandrite Tsarstone Collectors Guide. 03 Jul 2010, 04:44 UTC. 03 Apr 2026 http://m.alexandrite.net/viewpage.html?id=GG-099-00004
MHRA style
David Weinberg, "Definition of Negative reading", Alexandrite Tsarstone Collectors Guide, 03 July 2010, 04:44 UTC, http://m.alexandrite.net/viewpage.html?id=GG-099-00004 [accessed 03 April 2026].
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