View source for Cabochon

{{Short description|Gemstone that has been shaped and polished}}
{{one source|date=October 2020}}
[[File:Turmalin-cabochon.jpg|thumb|A collection of [[tourmaline]] cabochons in a variety of colours]]

A '''cabochon''' ({{IPAc-en|'|k|æ|b|u|ʃ|ɒ|n}}; {{etymology|frm|caboche|head}}) is a [[gemstone]] that has been shaped and polished, as opposed to [[facet]]ed. The resulting form is usually a convex (rounded) [[obverse]] with a flat reverse.<ref>{{cite book |title= Rock and Gem |publisher= [[DK (publisher)|DK]] |isbn= 0-7566-0962-3 |edition= 1st American}}</ref> Cabochon was the default method of preparing gemstones before [[lapidary#Cutting | gemstone cutting]] developed.<ref>
{{cite book
 |title                = Cutting and Polishing Gemstones - A Collection of Historical Articles on the Methods and Equipment Used for Working Gems
 |url                  = https://books.google.com/books?id=HHB-CgAAQBAJ
 |publisher            = Read Books Ltd
 |publication-date     = 2014
 |isbn                 = 9781473395398
 |access-date          = 21 August 2022
 |quote                = The cutting and carving of gems were probably first done in ancient Babylon several thousand years before Christ.
}} 
</ref>

==Application==
Cutting ''en cabochon'' (French: "in the manner of a cabochon") is usually applied to opaque gems, while faceting is usually used for transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the [[Mohs scale of mineral hardness |Mohs hardness scale]] are easily scratched, mainly by [[silicon dioxide]] in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident.

In asteriated stones such as star [[sapphire]]s and [[chatoyancy |chatoyant]] stones such as cat's eye [[chrysoberyl]], a [[elliptic dome| domed]] cabochon cut can show the star or eye, which would not be visible in a faceted cut.

The usual shape for cutting cabochons is an [[ellipse]] because the eye is less sensitive to small asymmetries in an ellipse than in a uniformly round shape such as a circle. Additionally, the elliptical shape, combined with the dome, is considered attractive. An exception is cabochons on some watch crowns, which are circular.

The procedure involves cutting a slab of the rough rock with a slab saw, and then stencilling a shape from a template. The slab is then trimmed near the marked line using a [[diamond blade]] saw—called a trim saw. Diamond-impregnated wheels or [[silicon carbide]] wheels can be used to grind the rough rock down. Most [[lapidary]] workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.{{cn|date=May 2022}}

Once the piece is trimmed it can be "dopped" or completed by hand. "Dopping" is normally done by adhering the stone with hard wax onto a length of wooden dowel called a "dop stick". The piece is then ground to the template line, the back edges may be bevelled, and finally the top is sanded and polished to a uniform dome.

== Gallery ==
<gallery>
Image:moonstone.cabochons.arp.jpg|[[Moonstone (gemstone)|Moonstone]] cabochons in a [[jewellery|jeweller's]] window
Image:Cabochon on watch crown.jpg|A round [[sapphire]] cabochon on the crown of a men's dress [[watch]].
Image:amber.pendants.800pix.050203.jpg|[[Amber]] pendants. The oval cabochon [[pendant]] is 52 × 32{{nbsp}}mm (2 × 1.3{{nbsp}}in).
</gallery>

== References ==
{{reflist}}

==External links==
{{commonscat|Cabochons}}
{{wiktionary|cabochon}}
* [https://web.archive.org/web/20110413022746/http://www.rockhounds.com/rockshop/oplc_cab.html Cabochon Making 101]


[[Category:Gemstone cutting]]