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| DESIGN STYLES |
These are some of the styles that influence the jewellery that is currently being designed and sold
in the marketplace. Some of the styles overlap in time while some are still being developed today.
|
| ART DECO |
The geometric style that succeeded Edwardian jewellery inspired by the French "Art Decoratif" movement,
from the 1920's and 30's. Zigzags and sharp angles rather than the curves of the Art Nouveau era characterized this
style. Coloured stones were utilized more, and the opaque stones such as jade, onyx and coral were set in geometric
shapes. Sleek animals such as Borzoi and Greyhound dogs were featured in some designs. The style started out with
relatively delicate designs but more geometric and angular than the previous Edwardian style and progressed to more
the more bold and blocky style also called Art Moderne.
|
| ART NOUVEAU |
A flowing style of jewellery with sinuous curves and naturalistic motifs produced mainly from
1890s - 1915. It typically has flowing lines and highly stylised depiction's of floral motifs, beautiful women, and
fantasy creations inspired by nature. A common motif was a women's head with flowing hair.
The name is derived from
La Maison de l'Art Nouveau, a gallery for interior design that was opened in Paris in 1895 by Japanese art collector
Siegfried Bing (later called Samuel Bing). While partly inspired by Japanese art, which was changing the western
attitude to Art, Art Nouveau was also influenced by Celtic, Gothic and Rococo art forms and was a reaction against
the academic schools that continued to differentiate between "lower applied and decorative art forms" and "higher
fine arts".
|
| ARTS & CRAFTS |
A design movement that began in the late 1800s as a rebellion against the mass-produced, machine
made designs of questionable aesthetic value common in the late Victorian era. The designers felt that their work
should look handmade, and therefore they often left hammer marks on the piece. Although pieces were made of gold,
silver was more commonly used to emphasize the craftsmanship of the piece rather than the intrinsic value of the
components. Stones were commonly less expensive cabochon stones such as moonstone,
mother of pearl, agates or amber. Enamel work was also used.
|
| CELTIC |
This style is derived from the myths and legends of the Celtic Races. Visual punning and
metamorphosis are common: the eye is tricked into seeing a number of animals or faces if the object is turned or
the patterns allowed to dissolve and reform themselves into different configurations. Geometry and numbers are
the bedrock of Celtic art. The circle and the number 3 are particularly significant. Underlying all of this art
is a deep appreciation of the potential for natural forms - leaves, animals, and faces - to shape the Celtic
ideas of beauty or good taste.
|
|
| DICHROIC GLASS |
see GLASS TYPES |
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| GEMSTONE CUTS |
|
| BAGUETTE |
A rectangular-shaped stone with rows of step-like facets. If the Baguette's two long sides taper
inward, it is called a Tapered Baguette. Baguettes in long, thin cut rectangles are often used as enhancements to
a larger centre stone, or on a watch bezel.
|
| BRILLIANT-CUT |
Brilliant cuts are scientifically found to reflect the most light from within the stone, and often
are considered to have the most brilliance of all cuts. A round brilliant-cut diamond has 58 facets. Other brilliant
cuts include the heart, oval, marquise and pear shaped.
|
| CABOCHON |
A cabochon is a stone cut in a facet-less style of cutting that produces a smooth surface. They
can be in many shapes, from round with high domes to squares.
|
| FACETS |
A Facet is the small polished surface of a muti-faceted Gemstone. This style of cutting gives the
stone many small faces at varying angles to one another. The placement, angle and shape of each facet are carefully
planned and executed to show the stone's inherent beauty, fire, color, and brilliance to the fullest advantage.
|
| GIRDLE |
The girdle is the widest perimeter of a gemstone and the dividing line between the crown and the
pavilion. Ideally the width of the girdle should be even and proportional to the cut of the stone. It can be either
polished or un-polished.
|
| STEP-CUT |
Is a cut with rows of facets that resemble the steps of a staircase. The Emerald Cut and the
Baguette are examples of the step cut.
|
|
| GLASS TECHNIQUES |
|
| HANDBLOWN GLASS |
The Glassblowing technique which was invented by the Phoenicians around 50 B.C.
The tip of the blowpipe is first preheated then dipped into molten glass in a furnace. The glass is 'gathered'
on to the blowpipe. The glass is then rolled on a marver, traditionally a slab of marble, but is more commonly
a fairly thick flat sheet of steel today. This forms a cool skin on the exterior of the molten glass and shapes
it. Then air is blown through the pipe to create a bubble. Then, one can gather over that bubble again to create
a larger piece.
A variety of tools including molds are then used to shape the glass. As the glass cools it begins to stiffen and
must be continuously reheated to allow shaping and reshaping. The glassblower uses a smaller furnace, a "glory
hole" for the re-heats.
When the piece is finished, it is placed in an kiln for annealing. This is the process of slowly cooling the glass
to room temperature to stabilize its delicate crystalline structure. Rapid temperature changes will cause the glass
to crack.
Patterns and color can be applied by rolling the molten glass in powdered color or larger pieces of colored glass
called frit. Complex patterns can be created through the use of rods of colored glass known as canes, or with
murrine (rods cut in cross-sections to reveal patterns).
|
|
| GLASS TYPES |
The main constituent of practically all glass is sand which by itself can be fused to produce glass
at temperature of about 1700°C. Adding other minerals and chemicals to sand can considerably reduce the melting
temperature and provide different chemical and physical properties.
|
| BOROSILICATE GLASS |
Borosilicate glass is a heat-resisting glass, better known in the UK as Pyrex™. It is made
mainly of 70-80% silica (SiO2) and 7-13% boric oxide (B2O3) with smaller amounts of
the alkalis (sodium oxide (Na2O) and potassium oxide (K2O)) and aluminium oxide
(Al2O3). This type of glass has a relatively low alkali content and consequently has good
chemical durability and thermal shock resistance (it doesn't break when changing temperature quickly). As a result
it is widely used in the chemical industry, for laboratory apparatus, for ampoules and other pharmaceutical containers,
for various high intensity lighting applications and as glass fibres for textile and plastic reinforcement.
|
| DICHROIC GLASS |
Dichroic glass is glass containing multiple micro-layers of metal oxides which cause visible light to
be split up into distinct beams of different colours or to absorb light with different polarizations by different
amounts. The earliest known example of an object made with Dichroic glass is The Lycurgus Cup, a 4th century AD cup
probably made in Rome and now exhibited in the British Museum.
|
| LEAD GLASS |
Commonly known as lead crystal, lead glass is used to make a wide variety of decorative glass
objects.
It is made by replacing the calcium oxide in Soda-Lime Glass with lead oxide and most of or all of the sodium oxide
with potassium oxide. The traditional English full lead crystal contains at least 30% lead oxide (PbO) but any glass
containing at least 24% lead oxide can be described as lead crystal. Glass containing less than 24% lead oxide, is
known simply as crystal glass. The lead is locked into the chemical structure of the glass so there is no risk to
human health.
Lead glass has a high refractive index making it sparkle brightly and a relatively soft surface so that it is easy to
decorate by grinding, cutting and engraving which highlights the crystal's brilliance making it popular for glasses,
decanters and other decorative objects.
|
| SODA-LIME GLASS |
By adding limestone to the Water Glass components, chemicals like calcium oxide (CaO) and magnesium
oxide (MgO) are added which result in a pure inert colourless glass freely able to transmit light. Other chemicals are
added to produce different properties and colours of glass. Most Soda-Lime Glass has a composition of 70% - 74% silica
(SiO2), 12% - 16% sodium oxide (Na2O), 5% - 11% calcium oxide (CaO), 1% - 3% magnesium oxide
(MgO) and 1% - 3% aluminium oxide (Al2O3).
|
| WATER GLASS |
The addition of sodium carbonate (Na2CO3), known as soda ash, to sand will
produce a mixture of 75% silica (SiO2) and 25% of sodium oxide (Na2O). This will reduce the
temperature of fusion of the glass to about 800°C. However, a glass of this composition is water-soluble hence
its name.
|
|
| GRAIN |
see WEIGHTS & MEASURES |
| GUILLOCHE |
see VITREOUS ENAMEL |
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|---|
| VITREOUS ENAMEL |
Vitreous Enamel is a glassy substance (powdered glass with colorants) fused normally onto metal using
heat (see basse taille, cloisonné, champlevé, guilloche, and plique à jour). Several layers of enamel may
be fired in succession. The enamels may be translucent or opaque. |
| BASSE TAILLE |
Basse taille is a type of enamelling in which translucent enamel (powdered glass with colorants) is
applied over a metal surface that has been textured by etching, engraving, stamping or chiselling by hand. This results
in the metal background and the pattern over it being seen through the translucent enamel. |
| CHAMPLEVÉ |
(meaning sunken enamel) Champlevé is a method of applying enamel (powdered glass with colorants)
to metal in which the design is first outlined on the metal surface by cutting lines into the surface by engraving,
etching or otherwise grooved . The engraved grooves are then filled with enamel, then fired to a glassy sheen, and
polished |
| CLOISONNÉ |
Cloisonné is a method of applying enamel (powdered glass with colorants) to metal or porcelain
in which the design is first outlined on the surface using a metal wire. The space between the wires is filled with
enamel and then fired to a glassy sheen. Technically the chamber formed by the wire enclosure is known as a cloison |
| GUILLOCHE |
Guilloche is a type of enamelling in which translucent enamel (powdered glass with colorants) is
applied over a metal surface that has been textured by engraving, stamping or chiselling using an engine-turning lathe.
This results in the metal background and the pattern over it which is extremely regular and precise, predominantly in
radiating patterns of sunburst and rosette design or linear patterns such as moiré silk and wave design, being seen
through the translucent enamel. |
| PLIQUE À JOUR |
Plique à jour is a back-less enamel that is a bit like stained glass. In plique à jour,
the enamel work is translucent (light shows through it) since the backing of the enamel is absent. Cells of enamel are
surrounded by delicate wire. Plique à jour is made by shaping cloisonné wire on a thin sheet of metal
(or mica) that will not bond to the enamel. Enamel (powdered glass with colorants) is fired into the wire cells. After
the enamel has melted and cooled, the backing (metal or mica) is peeled away or may be etched away and the translucent
enamel is left suspended in a supporting framework of cloisonné wire. |
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| WATER GLASS |
see GLASS TYPES |
|
| WEIGHTS & MEASURES |
|
| AVOIRDUPOIS |
Avoirdupois is a weight system, utilized by the United States and some Commonwealth Countries, for measuring commodities except precious metals, precious stones and medicines. The unit weight is the pound (7000 grains) and is divided into 16 ounces. This system was made illegal for trade to the public in England from 1st Jan 2000 and replaced by the metric |
| CONVERSION TABLE |
| |
Grains |
Grams |
Penny-
Weights |
Troy
Ounces |
Avoir-
dupois
Ounces |
Avoir-
dupois
Pounds |
Troy
Pounds |
| 1 Grain |
1 |
0.064799 |
0.041667 |
0.002083 |
0.002286 |
0.000143 |
0.0001736 |
| 1 Gram |
15.4324 |
1 |
0.643014 |
0.032149 |
0.035274 |
0.002205 |
0.0026791 |
1 Penny-
Weight |
24 |
1.555174 |
1 |
0.05 |
0.054857 |
0.003429 |
0.0041667 |
1 Troy
Ounce |
480 |
31.10348 |
20 |
1 |
1.097143 |
0.068571 |
0.0833333 |
1 Avoir-
dupois
Ounce |
437.5 |
28.34952 |
18.22917 |
0.911458 |
1 |
0.06250 |
0.0759549 |
1 Avoir-
dupois
Pound |
7000 |
453.5924 |
291.6667 |
14.58333 |
16 |
1 |
1.215278 |
1 Troy
Pound |
5760 |
373.2417 |
240 |
12 |
13.16571 |
0.822857 |
1 |
|
| GRAIN |
One of the earliest units of weight standardized in 1233 by Henry III. One grain being the equivalent of one grain of barley. It was found that 32 grains of dry wheat taken from the middle of the ear weighed the same as 24 grains of barley and barley was easier to obtain. |
| PENNYWEIGHT |
One of the earliest units of weight standardized in 1233 by Henry III. One pennyweight being the equivalent of 32 grains of dry wheat taken from the middle of the ear. This was also the nominal weight of silver in an English silver penny of that time. |
| TROY |
Troy is a weight system for measuring precious metals and precious stones. The Troy pound (5760 grains) is divided into 12 Troy ounces. It is possibly named after a weight used at the annual fair at Troyes in France in the Middle Ages. |
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