Jargoon

Jargoon

A Jargoon or jargon (occasionally in old writings jargounce and jacounce) is name applied by gemologists to those zircons which are fine enough to be cut as gemstones, but are not of the red color which characterizes the "hyacinth" or jacinth. The word is related to Arab "zargun" (zircon). Some of the finest jargoons are green, others brown and yellow, whilst some are colorless. The colorless jargoon may be obtained by heating certain colored stones. When zircon is heated it sometimes changes in color, or altogether loses it, and at the same time usually increases in density and brilliancy. The so-called "Matura" diamonds, formerly sent from Matara (or Matura) , in Sri Lanka, were decolorized zircons. The zircon has strong refractive power, and its lustre is almost adamantine, but it lacks the fire of the diamond. The specific gravity of zircon is subject to considerable variation in different varieties; thus Sir A. H. Church found the specific gravity of a fine leaf-green jargoon to be as low as 3.982, and that of a pure white jargoon as high as 4.705. Jargoon and tourmaline, when cut as gems, are sometimes mistaken for each other, but the specific gravity is distinctive, since that of tourmaline is only 3.103. Moreover, in tourmaline the dichroism is strongly marked, whereas in jargoon it is remarkably feeble. The refractive indices of jargoon are much higher than those of tourmaline.

References

* [http://www.farlang.com/gemstones/kunz_gems_and_precious_stones/page_120 Kunz: Gems and Precious stones of North America; Zircon]


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • jargoon — or jargon noun Etymology: French jargon more at zircon Date: 1769 a colorless, pale yellow, or smoky zircon …   New Collegiate Dictionary

  • jargoon — noun A variety of zircon …   Wiktionary

  • jargoon — n. colorless or smoky kind of zircon …   English contemporary dictionary

  • jargoon — jar·goon …   English syllables

  • jargoon — noun a colorless (or pale yellow or smoky) variety of zircon • Syn: ↑jargon • Hypernyms: ↑zircon, ↑zirconium silicate …   Useful english dictionary

  • Zirconium — (pronEng|zɚˈkoʊniəm, IPA|/ˌzɝˈkoʊniəm/) is a chemical element with the symbol Zr and atomic number 40. It is a lustrous, gray white, strong transition metal that resembles titanium. Zirconium is used as an alloying agent due to its high… …   Wikipedia

  • Witch World — The Witch World by Andre Norton is a long series of fantasies laid in a parallel universe where magic works and, at the beginning at least, is the exclusive property of women. The series combines many traits of high fantasy and sword and sorcery …   Wikipedia

  • English words first attested in Chaucer — Contents 1 Etymology 2 List 2.1 Canterbury Tales General Prologue …   Wikipedia

  • Jargon — For Wikipedia jargon, see Wikipedia:Glossary. For the gemstone, see Jargoon. For prelinguistic children s speech (jargon stage), see babbling. Jargon is terminology which is especially defined in relationship to a specific activity, profession,… …   Wikipedia

  • Zircon — Not to be confused with zirconia or cubic zirconia. This article is about the mineral. For other uses, see Zircon (disambiguation). Zircon Zircon crystal from Tocantins, Brazil (2×2 cm) …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”