A heating process whereby an alloy is heated to a certain temperature for a fixed time to change its properties. Generally, material that has been hardened by cold-working is annealed to soften it and to restore its ductility/malleability. Annealing can also be used to stress-relieve the metal or to age-harden it .
A small, simple drill for drilling by hand when a more precise application is required. The mechanism consists of a central helical shaft and a spring-loaded sliding collar. Moving the collar repeatedly up and down causes the shaft to rotate.
The technical term used for the quantitative chemical analysis of a material, or object, for one specific metal or chemical element of particular interest. It is often associated with the analysis of ores and metals. In the context of jewellery, assaying means the determination of the precious metal content of the item, such as gold in gold jewellery.
The laboratory where a jewellery item is sampled and analysed (assayed) to check that it conforms to the legal standard and then hallmarked. In the UK, the Assay Offices are independent of the trade.
Assay Office technician
A person trained and employed by an Assay Office to carry out the assaying and hallmarking processes according to the standard procedures.
Any one of the metals used in alloys that are not classed as precious metals, such as copper, nickel, zinc and tin, or metallic impurities such as lead.
bench peg / bench pin
A useful device attached to the work bench comprising a tapered wooden piece, typically made from beech, which is affixed via a clamp, and used to support the item or tool during the manufacture of jewellery or silverware.
An apron of material, fitted under the edge of the work bench, designed to catch all particles (saw dust, filings, etc.) of materials from the manufacture of jewellery at the work bench, particularly to enable economic recovery of the precious metals that would otherwise be lost on the floor. Traditionally made from leather, but nowadays also made from other flame retardant materials.
A small stick, usually wooden, covered in abrasive paper (leather or chamois or similar) and used for buffing or polishing.
A less aggressive polishing process used to smooth a surface, in which the item is subjected to movement of a buffing tool, such as a wheel or stick, to which an abrasive may be loosely applied.
The process of rubbing the surface with a hard tool (burnisher - typically made in a hard steel or agate) to produce a smooth and lustrous (polished) surface. The rubbing action moves material over the surface to fill in scratches etc. to give a mirror-like finish.
A hand punch, consisting of a short steel bar with a hardened conical point at one end, used for marking by indentation the centres of holes to be drilled. This aids the drill bit to drill in the correct place without wandering over the surface.
A pure metal with good ductility and conductivity and a red colour. It has an atomic number of 29, and density of 8.93 g/cc. It is a sister metal to silver and gold (lies in the same column of the Periodic table of elements). It is freqently used in carat gold and silver alloys to impart strength and hardness and to modify the colour of carat golds towards red.
cutting and piercing
A process for cutting out pieces of metal from a part, using cutting tools (hand or mechanical) or a laser, to produce a network of shaped holes in the item for a decorative effect and/or to lighten it.
The preparation of a plan or graphic picture/sketch of an object so that it can be made. This may be for decorative effect (as in jewellery) or for a functional purpose such as a machine (as in aeroplanes, cars, electronic devices, etc.). The person who creates the design is a designer, and may have an artistic or technical/engineering background. Most jewellery and silverware designers have an artistic background.
Diamond is a natural mineral and a form of the element carbon, and has the highest hardness and thermal conductivity of all natural materials. It is usually transparent, colourless and highly refractive to light (hence it glitters well as a gem stone). It is used as a precious gem stone in jewellery. Its high level of hardness also makes it useful for the cutting and polishing of objects.
A diamond mounter is a skilled craftsperson who makes the precious metalwork into which gemstones will be set. Traditionally this shows the minimal amount of metal whilst still retaining strength and security for the stones.
Dividers are simple adjusable tools with two pointed legs, used in the measurement of lines and the distances between two points, or the division of them. They can also be used to scribe circles into the surface of a metal, like a pair of compasses, or to scribe lines parallel with the edge of the metal.
An instrument with a sprung mechanism that is calibrated in 1/10mm for quick and accurate measuring of external dimensions.
A vitreous (glassy) decorative coating applied to a piece of jewellery or silverware by baking in a furnace (kiln) to give a smooth and hard surface. It is applied to the surface of an object as powdered coloured glass, and is fused by heating. Beautiful patterns and effects can be obtained by applying different colours selectively on the surface (e.g. cloisonné) or single transparent colours to engine turned surfaces (e.g. guilloche). Enamels can be transparent or opaque. This is a skilled technique practiced by an enameller.
An engraver is a specialist who has perfected the skill of cutting images into or onto the surface of metal using hand or machine engraving techniques.
A technique of decorating the surface of a metal or gemstone by cutting incised lines, characters, or patterns into the surface. It is usually done with a hard steel sharply pointed tool (graver) by skilled craftspeople (engravers), often with calligraphy skills.
The removal of metal from a piece with an iron file (tool), moved by hand over the piece where metal removal is required to achieve the desired shape and size. The metal is removed as small particles known as filings. This is an operation requiring considerable hand skills and good technique.
Similar to a hand file, but with a slight taper to the profile, narrower at the end furthest from the handle.
The setting (fixing) of gem stones into a jewellery piece so that they are held firmly in the correct position. There are a number of setting styles: prong (claw) settings are the most common and simple. Others include bezel, channel, bead and burnish. A person skilled in setting of gem stones is known as a gem setter or stone setter.
A copper-zinc alloy (brass), typically 5% zinc but ranging up to 25% zinc, used as a base for gilding, i.e. for a coating of gold, often applied by electroplating. The colour of gilding metal varies from red at 5% zinc to yellow at 15%. Gilding metals are also used for enamelling and the manufacture of rolled gold.
gold (9 carat)
9 carat gold is a gold alloy that contains a minimum of 37.5% gold (375 fineness), typically alloyed with copper, silver and zinc to produce red to yellow to white colours.
gold (14 carat)
14 carat gold is a gold alloy that contains a minimum of 58.5% gold 585 fineness), typically alloyed with copper, silver and zinc to produce red to yellow colours. White coloured 14 ct golds may contain other metal additions such as nickel.
gold (18 carat)
18 carat gold is a gold alloy containing a miniimum of 75.0% gold (750 fineness), typically alloyed with copper, silver and zinc to produce red to yellow to green golds. White coloured 18 ct golds may contain other additions such as nickel and palladium.
gold (22 carat)
22 carat gold is a gold alloy containing a minimum of 91.6% gold (916 fineness), typically alloyed with copper and silver to produce a reddish to yellow colour. White colour is not possible at 22 carat.
gold (24 carat)
24 carat gold is nominally pure gold, but its actual minimum gold content can vary around the world according to local national standards. Two standards are typically recognised in the UK: 990 fineness (99.0%) and 999 fineness (99.9%).
A hallmark is a mark applied (by a stamp or by laser engraving) to a piece of jewellery by an Assay Office, to show that the piece has been sampled and assayed and found to conform to the relevant legal precious metal standard. The process of assaying and applying the hallmark is known as hallmarking.
A file of rectangular section with parallel sides.
A hammer is a basic tool comprising a heavy (weighted) head and handle, used for beating (hammering) a piece of metal (or other material) to change its shape towards that desired, or to drive in a nail or other fastening. The head is swung by hand, typically several times, against the piece being hammered to impart a mechanical impact. Hammers come in a range of sizes, weights, and head shapes to suit the nature of the work being performed.
An ingot is a mass of metal, typically in bar or block shape, made by casting molten metal (pure or alloyed) into an ingot mould and allowing it to solidify upon cooling to a standard shape, suitable for storage or subsequent processing to the desired shape for its end use. For precious metals, ingots can vary in size and may also be used as an investment product in standard sizes (weights).
This is a specially designed work bench which enables jewellers to manipulate pieces of metal and produce items of jewellery. It will contain their tools and other materials in drawers and shelves, as well as a bench peg and bench skin. It allows an organised and practical workspace for the jeweller to produce their jewellery.
A kiln (a furnace or oven) is a thermally insulated chamber that allows items (typically metals or ceramics) to be heated to desired temperatures in order to optimise their properties or change their state. In jewellery, a kiln is used to 'burn out' the ceramic mould used for investment (lost wax) casting of jewellery items in precious metals prior to casting, or for firing enamel.
An artisan (worker) who cuts, grinds and polishes stones, minerals and gem stones (other than diamonds) into decorative items, using a variety of lapidary techniques and equipments, typically for use in jewellery.
A term used in the jewellery trade to describe the small metal particles (filings and other shavings) in precious metal alloys that are left over from making jewellery by hand at the work bench. It is equivalent to the sawdust produced when sawing wood. It will contain impurities such as organic matter, iron fron the files, pieces of binding wire, etc. as well as the precious metal filings. Lemel is treated and melted down to a bar before being sent for refining to recover the precious metals.
Marking out (layout) is the process of transferring a design or pattern to a workpiece. It is the first step in the manufacturing process and can be done by hand or machine, using various tools for measurement and scribing the design onto the surface of the workpiece.
Measuring is the assignment of a number (numerical value) to some property of an item or material to gauge its magnitude. In jewellery making, we typically measure physical dimensions such as length or breadth, volume or mass (weight), or others such as temperature, colour, density, reflectivity, hardness or strength.
A chemical compound comprising at least one atom of oxygen and one atom of another element, usually a metal. Most metals will form oxides, typically if heated to a high temperature. An example is the black copper oxide that forms on the surface of copper or carat gold when heated (e.g. during annealing or casting). Alumina (a ceramic) is an oxide of aluminium while silica (sand) is an oxide of silicon.
One of the six platinum group metals, palladium is a ductile metal with an atomic numer of 46 and a density of 12.02 g/cc, much lower than gold or platinum. It has good corrosion resistance, a good white colour, and is a hallmarkable jewellery metal in its own right. It is used in jewellery as an alloying addition to carat golds to impart a white colour, and is also used in platinum alloys.
A small electric drill with a flexible shaft and range of speeds that is suspended above the workbench and used for drilling, grinding and polishing operations by the jeweller. It is generally operated by a foot pedal, giving the jeweller precise control and speed of rotation. It is a flexible tool found on most work benches.
personal protective equipment (PPE)
PPE is protective clothing, googles, helmets, facemasks, footwear and the like, designed to protect the worker from hazards and injury. Hazards include physical, electrical, thermal (heat), chemical, biohazards and particulate matter, generally airborne. There is legislation in most countries, including the UK, that requires employers to ensure their employees are suitably protected against such hazards. Some PPE is mandatory and must be worn in particular environements and situations..
A process of cutting out pieces of metal from a part, by hand or mechanically, using cutting or laser tools to produce a network of shaped holes in the item for a decorative effect and/or to lighten it.
A pickle is an acid treatment used to remove oxides and scales from the surfaces of workpieces. Typically a 10% dilute sulfuric acid solution is used, but it is hazardous to store and use. A safety pickle consists of sodium hydrogen sulfate mixed in water at 220g/litre; when dissolved & heated, it is nearly as effective and lasts longer, and much safer to store and handle.
An electric drill mounted on a stand, often with an adjustable height. This enables more secure and precise drilling of holes in workpieces.
One of the six platinum group metals, platinum is a ductile metal with an atomic number of 78 and a density of 21.37g/cc. It has very good corrosion resistance and a high melting point of 1769°C, and a good white colour. It is a jewellery metal, often used at 900 or 950 fineness and alloyed with other platinum group metals as well as copper, cobalt and gold.
Gold, silver and the 6 platinum group metals - platinum, palladium, iridium, ruthenium, rhodium and osmium.
A slim, long cylinder of a material such as metal or wood, typically round but alternatively rectangular in section. A rod is often produced by rolling an ingot of metal, and may be used to draw down to a finer cross-section to produce wire.
A machine comprising a pair (or more) of hard steel rolls that rotate. A metal block or rod is passed through the rolls, set at a smaller gap than the thickness of the metal, and the force exerted by the rolls reduces the thickness of the metal. This is done at room temperature (cold-working) or at high temperature (hot-working).
A hard steel file with a round cross-section, used for filing out (fine cutting to remove metal) from curved surfaces and for enlarging holes.
Spectacles (glasses, goggles, eyewear) used during work to protect the eyes from harmful dirt, dust and debris, particularly flying debris ejected from a machine. They are often part of personal protective equipment. The wearing of safety spectacles is usually mandatory in the workplace. In the UK, Spectacles must conform to DIN EN 166, a European standard for all personal eye protection requirements.
A saw blade is a hard steel flexible blade with sharp teeth along one edge, used for cutting through materials such as metal or wood. It is typically a long thin ribbon of metal for fitting into a saw frame, but may also be a circular disc with teeth around the edge for fitting onto a rotating saw machine. They come in a range of sizes and a range of teeth dimensions to suit the application.
A saw frame is a steel frame, generally rectangular, with a handle for holding a saw blade under tension to enable a material to be cut. It is also known as a bow saw. The shape and size of the frame can vary to suit the type of work being done.
A device for measuring the mass or weight of an object. It may be mechanical or electronic and has a readout scale or display to indicate the weight being measured.
The inscribing of a "V" cut into the surface of a work piece, generally to fold a sheet of metal to a desired angle. This may be done using hand or mechanical methods.
A hand tool used in metal working to mark/scribe lines on the workpiece prior to machining (cutting/ filing/sawing, etc.). It comprises a hard steel pointed needle set in the tool that is pressed into and drawn along the surface to create the desired scribed line.
A pure (precious) metal with a good white colour and excellent ductility and condictivity (electrical & thermal). It has an atomic number of 47 and a moderate density of 10.5 g/cc. It has a melting point of 961°C. It is a jewellery metal, usually alloyed with copper, and is also used as a major alloying addition to carat gold alloys; it tends to whiten the yellow colour of gold.
The art of turning silver sheet metal into hollow ware (e.g. dishes, bowls, porringers, cups, candlesticks, vases, ewers, urns, etc.), flatware (silverware) and other articles of household silver, church plate or sculpture. It is carried out by a trained craftsman qualified as a Silversmith.
A small decorative article or ornament, usually in silver, produced by skilled craftsmen and often involving stamping. Examples include small boxes, miniature figures and items, etc. and have detailed decoration on the surfaces and may be enamelled. The craftspeople who carry out this work are known as smallworkers.
The art of producing hollow forms/shapes from sheet metal, usually in silver, by means of a shaped chuck spinning in a lathe. The metal is spun in the lathe and a tool is applied to bend the metal into the desired shape. A variety of shapes and forms can be produced by this technique which are seamless. It is used for producing shapes that are difficult to form with dies and press, and used for hollow forms such as cups, bowls and stems. The skilled craftsperson who practices this technique is known as a spinner.
Also known as squaring the diamond, this term refers to orienting the stone in the jewellery item so that it is shown off to best effect. When setting a round brilliant diamond in a four prong setting, there is some debate among stone setters on how to orient the stone. The term is derived from the fact that if you look straight down on a round brilliant diamond, the table facet and the star facets, when combined together, create a square. The corners of this square are where the prongs are set to hold it in the best position.
A simple measuring instrument (a ruler made in steel) that is used for measuring distances and ruling straight lines.
A common standard silver alloy comprising 92.5% silver (925 fineness), alloyed generally with copper, which may also contain other alloying metals such as zinc and germanium. It is typically used for jewellery and silverware.
The permitted variations in the measurement of an item against the set/specified value. In jewellery, it may be a physical dimension, weight, volume, chemical composion including precious metal content, or colour, for example.
In jewellery, this term refers to a blowlamp/blowtorch used for heating up a workpiece. Generally fuelled by gas, it comprises a torch head in which two combustable gases are mixed and ignited to form a hot flame that is used to heat up the work piece(s).
A long hollow cylinder, usually in metal, typically used for the passage of fluids (gas and liquid). In jewellery, a tube (also called a chenier) in precious metal may be used to manufacture rings (by cutting off sections of tube) or to assist in the manufacture of a component from the tube.
A general measuring tool for the accurate measurement of outside diameters, bores, hole depth, thickness & shoulder distance. It has a vernier scale, which is a visual aid for taking an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, thereby increasing resolution and reducing measurement uncertainty.
A long thin cylinder of metal, much finer than a rod, generally flexible. In jewellery, precious metal alloys may be drawn down to fine wire for use as decoration on pieces or as solders, for example.
A working drawing is usually a scale drawing which serves as a guide for construction or manufacture, intended for direct use in the workshop.
X-ray fluorescence machine
X-ray fluorescence technology is one of the simplest, most accurate and most economic analytical methods for the determination of the chemical composition of materials. It requires very little sample preparation, and is both non-destructive and reliable. It is used in the assaying of precious metals due to its quick, accurate and non-destructive nature.
0 - 9
925 silver (Sterling)
A common standard silver alloy comprising 92.5% silver (925 fineness), alloyed generally with copper but which may also contain other alloying metals such as zinc and germanium. It is often used for jewellery and silverware, and is known as Sterling silver.
958 silver (Britannia)
A standard silver alloy comprising 95.8% silver (985 fineness), alloyed generally with copper. Not so freqently used today for jewellery and silverware as Sterling silver, it is known as Britannia silver.
999 silver (Fine)
A pure grade of silver assaying at 99.9% purity, known also as fine silver.