Carnelian

Carnelian
Carnelian
General
Category	Chalcedony variety
Formula; (repeating unit)	Silica (silicon dioxide, SiO2)
Crystal system	Trigonal
Identification
Formula mass	60 g/mol
Color	Brownish-red
Cleavage	Absent
Fracture	Uneven, splintery, conchoidal
Mohs scale hardness	6 - 7
Luster	Vitreous, dull, greasy, silky
Streak	White
Diaphaneity	Translucent
Specific gravity	2.59 - 2.61
References

Carnelian (also spelled cornelian^[2]) is a brownish-red mineral commonly used as a semi-precious gemstone. Similar to carnelian is sard, which is generally harder and darker (the difference is not rigidly defined, and the two names are often used interchangeably). Both carnelian and sard are varieties of the silica mineral chalcedony colored by impurities of iron oxide. The color can vary greatly, ranging from pale orange to an intense almost-black coloration. It is most common in Brazil, India, Siberia and Germany.

History

Carnelian intaglio with a Ptolemaic queen, Hellenistic artwork, Cabinet des Médailles

Polish signet ring in light-orange Carnelian intaglio showing Korwin coat of arms

The red variety of chalcedony is known as beads since the Early Neolithic in Bulgaria. The first faceted (with constant 16+16=32 facets on each side of the bead) carnelian beads are described from the Varna Chalolithic necropolis (middle of the 5th mill. BC) (Kostov, Pelevina, 2008). The bow drill was used to drill holes into carnelian in Mehrgarh between 4th-5th millennium BC.^[3] Carnelian was recovered from Bronze Age Minoan layers at Knossos on Crete in a form that demonstrated its use in decorative arts;^[4] this use dates to approximately 1800 BC. Carnelian was used widely during Roman times to make engraved gems for signet or seal rings for imprinting a seal with wax on correspondence or other important documents. Hot wax does not stick to carnelian.^[5] Sard was used for Assyrian cylinder seals, Egyptian and Phoenician scarabs, and early Greek and Etruscan gems.^[6] The Hebrew odem (also translated sardius), the first stone in the High Priest's breastplate, was a red stone, probably sard but perhaps red jasper.^[6] In Revelation 4:3, the One seated on the heavenly throne seen in the vision of John the apostle is said to "look like jasper and 'σαρδίῳ' (sardius transliterated)". And likewise it is in Revelation 21:20 as one of the precious stones in the foundations of the wall of the heavenly city.^[7]

Etymology

Although now the more common term, "carnelian" is a 16th-century corruption of the 14th-century word "cornelian" (and its associated orthographies corneline and cornalyn).^[9] Cornelian, cognate with similar words in several Romance languages, comes from the Mediaeval Latin corneolus, itself derived from the Latin word cornum, the cornel cherry,^[10] whose translucent red fruits resemble the stone. The Oxford English Dictionary calls "carnelian" a perversion of "cornelian", by subsequent analogy with the Latin word caro, carnis, flesh. According to Pliny the Elder, sard derived its name from the city of Sardis in Lydia from which it came, and according to others, may ultimately be related to the Persian word سرد sered, meaning yellowish red.^[6]

Distinction between carnelian and sard

The names carnelian and sard are often used interchangeably, but they can also be used to describe distinct subvarieties. The general differences are as follows:^[6]

	Carnelian	Sard
Color	Lighter, with shades ranging from orange to reddish brown	Darker, with shades ranging from a deep reddish brown to almost black
Hardness	Softer	Harder and tougher
Fracture	Uneven, splintery and conchoidal	Like carnelian, but duller and more hackly (having the appearance of something that has been hacked, i.e. jagged)

All of these properties vary across a continuum, so the boundary between carnelian and sard is inherently blurry.

References

^ Rudolf Duda and Lubos Rejl: Minerals of the World (Arch Css, 1990)
^ Websters New World College Dictionary. Fourth Edition. 2001. Editor in chief Michael Agnes.
^ Kulke, Hermann & Rothermund, Dietmar (2004). A History of India. Routledge. 22. ISBN 0-415-32920-5.
^ C. Michael Hogan, Knossos fieldnotes, Modern Antiquarian (2007)
^ Section 12 of the translation of Weilue - a 3rd-century Chinese text by John Hill under "carnelian" and note 12.12 (17)
^ ^a ^b ^c ^d Chisholm, Hugh, ed. (1911). "Sard" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
^ Revelation 4:3
^ "Egyptian - Necklace". The Walters Art Museum.
^ "'Cornelian'". Oxford English Dictionary. Oxford University Press. Retrieved 14 February 2012.
^ Chisholm, Hugh, ed. (1911). "Carnelian" . Encyclopædia Britannica (11th ed.). Cambridge University Press.

External links

[1] Rudolf Duda and Lubos Rejl: Minerals of the World (Arch Css, 1990)

[2] Websters New World College Dictionary. Fourth Edition. 2001. Editor in chief Michael Agnes.

[Kulke&R.-3] Kulke, Hermann & Rothermund, Dietmar (2004). A History of India. Routledge. 22. ISBN 0-415-32920-5.

[4] C. Michael Hogan, Knossos fieldnotes, Modern Antiquarian (2007)

[5] Section 12 of the translation of Weilue - a 3rd-century Chinese text by John Hill under "carnelian" and note 12.12 (17)

[1911EB_sard-6] Chisholm, Hugh, ed. (1911). "Sard" . Encyclopædia Britannica (11th ed.). Cambridge University Press.

[7] Revelation 4:3

[8] "Egyptian - Necklace". The Walters Art Museum.

[9] "'Cornelian'". Oxford English Dictionary. Oxford University Press. Retrieved 14 February 2012.

[10] Chisholm, Hugh, ed. (1911). "Carnelian" . Encyclopædia Britannica (11th ed.). Cambridge University Press.

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