Editing Lapidary (section)

==Techniques==
[[File:Zafirs-treball2.jpg|thumb|alt=A Sri Lankan man works on some jewellery on a worktop lit by overhead lamps.|A jewellery worker in Sri Lanka]]
There are three broad categories of lapidary arts: [[tumble polishing|tumbling]], [[cabochon|cabochon cutting]], and [[facet cutting|faceting]]. Among a modern gemcutter's work are the following activities:
* Positioning rough stone in a holder, and holding the stone against the edge of a revolving saw or lapidary slitter impregnated with [[diamond]] dust to cut and slit stone.
* Removing cut stone and placing it in lapidary stick. A gemcutter then selects the shaping wheel and applies abrasive compound. They hold a lapidary stick against the revolving shaping wheel and lapidary disk to further shape stone and grind facets.
* Depositing stone within a barrel with both water and a grinding/polishing medium and either vibrating or rotating said barrel using friction to grind and polish the stones over time.<ref>{{Cite web|title=Lapidary Fundamentals: Gemstone Tumbling|url=https://www.gemsociety.org/article/lapidary-fundamentals-gemstone-tumbling/|access-date=2022-02-22|website=International Gem Society|language=en}}</ref>
* Examining stone for accuracy of cut, using a magnifying glass. A gemcutter polishes stone, using felt or canvas-covered polishing wheel, and polishing compounds, such as [[Rotten stone|tripoli]] or [[jeweler's rouge]].
* Possibly using a mechanical [[Faceting machine|facet-cutting device]]. A gemcutter may cut and polish diamonds for industrial purposes, and be designated as an industrial diamond polisher.
* The [[Mohs scale|Mohs hardness scale]]<ref>{{Cite web|title=Mohs Hardness Scale (U.S. National Park Service)|url=https://www.nps.gov/articles/mohs-hardness-scale.htm|access-date=2022-02-22|website=www.nps.gov|language=en}}</ref> is a commonly used tool in lapidary to help measure a mineral's scratch hardness. A mineral's scratch hardness is measured by seeing how easily scratched it is, and what other minerals on the Mohs hardness scale can scratch it. This tool is helpful in indicating what different lapidary methods should be used on the material.

===Cutting===
{{More|Diamond blade}}
Cutting of [[Mohs scale of mineral hardness|harder]] stones is done with a diamond-edged saw. For softer materials, a medium other than diamond can be used, such as [[silicon carbide]], [[garnet]], [[Emery (mineral)|emery]], or [[corundum]]. [[Diamond cutting]] requires the use of diamond tools because of the extreme hardness of diamonds. The cutting, grinding, and polishing operations are usually lubricated with water, oil, or other liquids. Beyond these broader categories, there are other specialized forms of lapidary techniques, such as casting, carving, jewelry, and [[mosaic]]s.{{Citation needed|date=April 2018}}

While the gemstone in the rough state may be trimmed to remove undesirable material or to separate it on a [[Cleavage (mineralogy)|cleavage line]] with a [[diamond blade]]d saw, accurately described as cutting and once done by the use of a [[chisel]] or similar tool to simply break off pieces that were usable as single gemstones, the actual shaping and polishing of a gemstone is a grinding or [[sanding]] process. This grinding and sanding is done using a [[lapping|lap]], a precision metal plate embedded with grit similar to the more familiar embedding of grit on paper the lap is of high precision particularly for flatness and turned by a motor. The grit material is normally diamond and sometimes corundum for their hardness. Only diamond is hard enough on the [[Mohs scale]] to shape and polish a diamond.

===Faceting===
{{main|Faceting machine}}
Faceting requires equipment allowing for very precise adjustment of angle and location around the gemstone for facet-placement, a process sometimes referred to as indexing. 
The design may be computer-generated or left up to the skill and expertise of the individual cutting the gemstone.

During the process of grinding, faceting, and lapping, the gemstone is usually affixed ("dopped") to a rod (frequently referred to as a "dop" or "dopstick") made of wood, or perhaps brass or steel, 
with [[dopping cement]], a specialized [[thermal adhesive]]. The dopstick can be hand-held or inserted into the indexing equipment for more precise faceting. A [[coolant]] then needs to be constantly applied to prevent softening of the cement. Diamonds, however, are held mechanically, or with low-[[melting point]] [[solder|tin-lead solder]], since the resultant heat generated by friction can be extreme, thus preventing the use of [[thermal adhesive]]s.

[[Cabochon|Cabochons]] - smooth-shaped gemstones without facets such as [[jade]] or [[turquoise]], and indeed most gemstones - are instead shaped and polished in much the same manner. They are usually left up to the skill and expertise of the individual cutting the gemstone and to similar equipment such as the [[lapping]] equipment.

===Polishing===
Most modern lapidary work is done using motorized equipment. Polishing is done with resin- or metal-bonded [[Emery (mineral)|emery]], [[silicon carbide]] (carborundum), [[aluminium oxide]] ([[corundum]]), or diamond dust in successively decreasing particle sizes until a polish is achieved. In older systems, the grinding and polishing powders were applied separately to the grinding or buffing wheel. Often, the final polish will use a different medium such as [[tin oxide]] or [[cerium(IV) oxide]].

The initial shaping and facet placement may be done using laps with grits of 220, 600, 1200. The polishing step, however, requires grits of a much higher grade, such as 8,000, 14,000, 50,000 and even 100,000. This grit is also embedded into a metal lap, but sometimes applied manually to the lap during polishing.

===Inlaying===
Another specialized form of lapidary work is the [[inlay]]ing of [[marble]] and gemstones into a marble matrix. This technique is known in English as ''[[pietra dura]]'', for the [[hardstone]]s that are used, like [[onyx]], [[jasper]] and [[carnelian]]. In [[Florence]] and [[Naples]], where the technique was developed in the 16th century, it is called {{lang|it|opere di commessi}}. The [[Basilica di San Lorenzo di Firenze|Medici Chapel at San Lorenzo]] in Florence is completely veneered with [[Inlay|inlaid]] hard stones. The specialty of ''[[micromosaic]]s'', which developed in the late-18th century in Naples and Rome, is sometimes covered under the umbrella term of lapidary work. In this technique, minute slivers of glass are assembled to create still life, cityscape views, and other images. In [[China]], lapidary work specializing in [[Chinese jade|jade]] carving has been continuous since at least the [[Shang dynasty]].{{citation needed|date=April 2018}}