Kundan - Meena

SDI: Where Creativity Meets Excellence.: Kundan - Meena

Gemology Guide - Physical Properties of Gemstones

SDI: Where Creativity Meets Excellence.: Gemology Guide - Physical Properties of Gemstones

Diamond Formation

The glitter of diamonds, the perfection of their facets and their scintillating fire always makes one wonder that how did these shining beauties come to existence? Diamonds are formed under certain precise conditions in the deep interiors of the earth. These sparkling fruits of nature are believed to be more than billions of years old and form under the stable continental plates. In this post we will unearth the procedure of diamond formation.

The formation of diamonds takes place under extreme conditions. Diamonds form mostly in the mantle which is below the surface layer of the earth at a distance of approximately 150 Kms. When carbon crystals are subjected to a temperature of 1050° C and a pressure of 45000-60000 Kilobars, is when the process of diamond formation begins. These conditions are not present uniformly in the layers of the earth. These conditions mostly exist under the stable continental plates. These stable parts are called cratons.

 

CRATONS

It is a fairly common belief that when a person or an object is subjected to immense pressure and difficulties they either they crack or come out victorious. The same is with the diamonds they undergo extreme heat and pressure in the interiors of  the earth but a slight change in the conditions can lead to formation of graphite.

 

GRAPHITE

There are two types of diamonds – P Type and E Type. P type diamonds are formed with the help of peridotitic rocks and E type are formed with the assistance of eclogitic rocks.  Peridotite and eclogite are referred to as source rocks as the diamonds form in these igneous rocks. These rocks exist under the earth in a molten state and they continuously emit carbon. The carbon atoms under the immense heat and pressure of the earth’s interiors start locking with each other. If the conditions are accurate diamond crystals start forming.

PERIDOTITE

Diamonds formed in the mantle are brought up to earth’s surface by the deep volcanic eruptions. These eruptions break the mantle and bring the diamonds to the surface. The rocks which transport the diamonds are kimberlite and lamproite. Kimberlite and lamproite are formed in the molten magma in the mantle.  The magma expands as it heats up and it passes through a fracture in the crust. While passing through a fracture it might come in contact with a diamond deposit and carry the diamonds along with it. The magma then continues to rise and the pressure decreases. With the decrease in pressure magma is able to travel at a very high speed of about 300 Kms/hour. At this stage some chemicals start to vaporise into carbon dioxide and water vapour. The speed of magma along with release of gases leads to an explosion. At this very point kimberlite pipes are formed. These pipes are where the majority of diamonds are found.

 

KIMBERLITE PIPE

Any change in vaporisation and the speed of magma can result in formation of graphite. The kimberlite or lamproite then solidifies creating a diamond rich deposit. This is what most of the diamond miners hunt for.

Diamonds go through a lot before one sees them glittering in a store’s display. They undergo extreme heat and pressure and are brought to the earth by violent eruptions. For years together they trapped there until unearthed by man. Thereafter, they are cut and polished and that’s when one sees the real beauty of diamonds.  And that is why it is said, to have an understanding of diamond formation is extremely important not only from technical aspects but also because so that one can appreciate this unique process and also how rare are fine gem quality diamonds.

Hallmarking

SDI: Where Creativity Meets Excellence.: Hallmarking

Gemology

SDI: Where Creativity Meets Excellence.: Gemology

Diamond Mining Companies

SDI: Where Creativity Meets Excellence.: Diamond Mining Companies

Pearls - Natural and Cultured

SDI: Where Creativity Meets Excellence.: Pearls - Natural and Cultured

TECHNIQUES OF METAL DECORATION (PART-2)

In the previous post of The Jewel Affair some very interesting techniques like Filigree, Repousse´ & Chasing and Enamelling were discussed in detail. In the proceeding post, subjects like acid etching, stamping, embossing and engraving will be dealt with.

Acid Etching: etching has been derived from a German word for ‘eat’. This technique literally lets the acid bite into the metal surface to create relief patterns. In other words it can be described as a technique which uses the concept of corrosion for metal decoration. The basic idea is to create a design on the metal and cover the areas which one wants in high relief with acid proof substance. Thereafter the metal plate is submerged in acid and then the exposed areas start corroding and creating relief patterns.

The earliest findings of this techniques dates back to 1500 A.D. The technique was most widely used for creating armours and art work but today the technique is more widespread. Nowadays it is also being used as a preliminary step in the process of enamelling.

The latest version of acid etching process is Photo Etching. In this process the metal sheet is firstly covered with photosensitive polymers to avoid any deforming of the metal because of its exposure to the ultra violet light. Then with the help of computer aided software patterns are created and transferred on the metal with the help of UV lights. Then the metal sheet is thoroughly cleaned and then it is laminated. The laminated piece is put into the photo tools and again exposed to UV lights. The selected areas of the laminate are converted into acid proof areas. The sheet is then sprayed with acid and corrosion takes place. Thereafter, the sheet is cleaned again and the result is smooth relief patterns.

The advantage of this method is its low cost of production; it is not a labour- intensive technique, requires less cleaning and finishing and the precision achieved is remarkable.

ACID ETCHING

Stamping: it is a procedure in which the metal is pressed between steel dies in a hydraulic press at very high pressure. This method is ideal for large scale production and is widely used for manufacturing coins, pendants, earrings and shanks. On a smaller scale it can be taken up individually with the help of stamps, hammer and other tools. Here the process is relatively simple when taken up individually than the other techniques. The only drawback is that the design options here are limited.

STAMPED JEWELRY

STAMPS

TOOLS FOR STAMPING

Embossing: under this technique the metal is usually punched from behind to create relief work on the other side. Varieties of tools are used to achieve the desired result. First and foremost the design is traced out on the metal foils or sheets with the help of a stylus, which is an embossing tool. The design is then worked around with a couple of more tools to create the relief. The height of the relief is a matter of personal choice. Finally some pointed tools are used to refine the design from front and the design is finished with buffing tools.

EMBOSSED JEWELRY

Engraving: it is an art of carving out designs on metal surfaces. A chisel is usually used to incise the design, which is also termed as a burin. Chisels come in various varieties and are used by metal workers on all sorts of metals like copper, steel, gold and silver. Engraving is used for various purposes like jewelry, armours, weapons and kitchenware. With technological advancement machines are created for engraving bigger sheets of metal and sometimes dyes are also used for engraving designs.

ENGRAVING

One can say that these techniques of metal decoration have revolutionised the way it was used by the pre-historic man. Owing to these techniques beautiful artwork started developing. When one looks back, these techniques also give us important clues about our ancestors and the way development came about in those times. So, these techniques have not only beautified the world around us but also show us how we have evolved through these centuries.

*Pictures adopted from Google.

RUBY - The Undisputed King of Gemstones [Part 2]

SDI -where creativity meets excellence

RUBY - The Undisputed King of Gemstones [Part 1]

SDI -where creativity meets excellence

TECHNIQUES OF METAL DECORATION (PART-1)

Development of human civilisation was heavily dependent on discovery of metals. Pre-historic man gradually understood the use of metals and started to use them for various purposes. He started fashioning them into weapons and tools. With the progress of time he discovered metals like copper, bronze, silver & gold. He started using these metals for personal adornment and one after the other advancements were made in the way jewelry was fashioned by him. As a result, beautiful techniques were developed to decorate metal.

This post of The Jewel Affair is an effort to explore the journey of how these techniques evolved over the centuries. Some of the most popular techniques are:

FILIGREE: it can be defined as an ornamental technique where twisted wires of silver and gold are joined together to create an open framework. The word filigree is derived from the Latin word filum meaning thread. Filigree is also known as telkari- Anatolian word meaning wire work.

Filigree is an ancient art which was practised by the Greeks and Etruscans (ancient Italian Civilisation). This art advanced the most in the period from the 6^th Century B.C- 3^rd Century B.C. In the Medieval times it was practised by the Moors of Spain. Moors were the Medieval Muslim inhabitants who practised this art to perfection and created exquisite designs. Around 600 A.D the Irish craftsmen became renowned for the variety they brought about in the art.

Filigree still exists in India, Mexico and Scandinavian countries. In India the craftsmen till date retain the patterns of the ancients Greeks. These patterns are believed to be passed on from the time the Greeks came to settle down in India. Cuttack in Orissa still showcases traditional filigree work.

Filigree is of two kinds:

Open: in open filigree the wirework is an open framework. There is no metal backing or support.

OPEN FILIGREE

 Closed: in closed filigree the framework is supported by a metal back.

CLOSED FILIGREE

REPOUSSE´ & CHASING: This is technique of freehand hammering which uses specific tools to create relief work. This technique is a combination of two techniques put together.

 Repousse´ is a French word which means to ‘push out’. In this technique the metal is hammered from both front and back to create a sculptural relief. It is believed to be an ancient technique. Armour plates decorated with this technique are found which date back to the 3^rd century B.C. Repousse` is of two kinds:

• Eastern Repousse´
• Western Repousse´

The difference between these two techniques is basically of the tool shapes and the angle at which the metal is struck. And the most notable difference is of the height and depth created in the relief. Eastern technique was used by ancient Egyptians and Greeks and Western technique moreover used in western Europe, Japan, Thailand and other parts of Asia.

The most famous examples of Eastern Repousse` are the Gold Mask of Tutankhamun and Vaphio cups. The biggest sculpture created with this technique is The Statue of Liberty.

GOLD MASK OF PHARAOH TUTANKHAMUN 

VAPHIO CUPS

 On the other hand, chasing is used only on the front side of the metal to bring finesse to the design. This is usually a slow process and there is no loss of metal. The only disadvantage of this process is that contact of tools with the metal is evident unlike other techniques.

A repousse` artist uses a working surface which is called the chaser’s surface. It is made of pitch which is a viscous polymer derived from coal tar, resin and plaster of Paris. This surface keeps the metal in place while it is hammered.

ENAMELLING: in this technique coloured powdered glass is used create a transparent coat on the metal. Powdered glass is fused on to the metal by application of heat, the glass then melts and flows and is fused to the metal. This is an ancient technique of decorating jewels and artefacts. The earliest remains of enamelled artefacts dates back to 13^th century B.C. This technique in modification was used largely by the Egyptians and Romans.

There are various enamelling techniques which are used, but this post deals with four most popular techniques:

CHAMPLEVE´: it is French word meaning ‘raised-field’. This technique blossomed fully in the 12^th century and was most popularly practiced in France and Italy. For Champleve` a slightly thicker metal sheet is used and patterns are developed by creating a low relief. Basically, the metal is shaved out a bit to create space for enamel to be filled in. The recessed areas are then filled with powdered enamels and heated so that the enamel melts. Enamel is built up in layers so that it reaches the same height as that of the remaining metal. This technique was used mostly with copper.

CHAMPLEVE´

BASSE-TAILLE: Basse-Taille literally means low cutting or engraving in French. It is

an extension of Champleve´ technique and developed to its best in 13^th-14^th century. It is slightly different from Champleve`. The basic difference is that the area which is shaved out, in that area a figure or a design is chased out and instead of powdered enamels transparent enamels are used. This technique is used on usually gold or silver. In Basse-Taille the metal shines through the transparent enamel and adds a beautiful glaze to the enamel. All these factors in totality give the enamelled object a three dimensional effect.

BASSE TAILLE

CLOISONNE´: the name of this technique is derived from the French word cloison, which literally means a cell. This art was most popular in the periods between the 6^th-12^th century in East Roman Empire and Gaul and Britain. In this technique flattened wires are soldered on a metal base. The attached wires result in creation of cells or compartments. These compartments are then filled with powdered enamel. The enamel is then heated and fused with the metal.

CLOISONNE´

PLIQUE-A´-JOUR: in French Plique-A´-Jour means ‘letting in daylight’. This technique is similar to Cloisonné except for the fact that the wirework created does not have any backing or metal attached to it and transparent enamel is suspended in the cells of the wirework and then heated. This is used to create a stained glass effect. Several transparent colored enamels are blended between the wires to give that delicate water color like appearance.

 

PLIQUE-A´-JOUR

Part-2 of this article will talk about some more interesting techniques like Acid Etching, Embossing and Stamping.

*Pictures adopted from Google.

Manufacturing Processes for Jewelry

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Perspective Drawing

The previous post of The Jewel Affair spoke about technical drawings. The two types of technical drawings commonly used are:

• Orthographic Representation (Article-6)
• Perspective Drawing

This article is about an introduction to the perspective drawings and its types. These technical drawings are very interesting and intricate at the same time. And is the most important link between the designer and the craftsman. One can use these drawings to provide the smallest of detail for the designed product.

But, how does one define perspective drawings?

Perspective drawing is a technique which is used to represent three dimensional images on a two dimensional plane. There are two main aspects of perspective drawing:

The size of the object seems to diminish according to the distance.

The tone and colors change as you move farther from the object.

One of the most important elements of a perspective drawing is a Horizon Line. This is directly opposite to the viewer’s eye level.

Types of Perspective Drawing:

One Point Perspective: it is named so because it uses only one Vanishing Point (vp) to draw an object. The vanishing point is usually on the horizon line. All parallel lines from the viewer’s angle recede to the horizon towards the vanishing point.

ONE POINT PERSPECTIVE DRAWING

EXAMPLE OF ONE POINT PERSPECTIVE

Two Point Perspective: this type of drawing uses two Vanishing Points (vp1 and vp2) and the lines are parallel to two different angles.

TWO POINT PERSPECTIVE DRAWING

EXAMPLE OF TWO POINT PERSPECTIVE

Three Point Perspective: as the name suggests it has three vanishing Points (vp1, vp2 & vp3). In addition to the two vanishing points the third Vanishing point is added either above or below the perpendicular, as to how the wall will recede in the ground or soar above. So, the vanishing point is considered either above or below the ground.

THREE POINT PERSPECTIVE DRAWING

EXAMPLE OF THREE POINT PERSPECTIVE 

Perspective drawings are used on a large scale by interior designers and architects. Three point perspectives are the most useful for a jewelry designer.

Technical drawings are the most useful tools in the hands of a designer and the most vital aid for a craftsman. It is the most crucial link between the artist and the worker. So, one must practice these drawings until perfection is arrived at.

Construction of perspective drawings is a complex and practical process. It is best understood practically in a class through an expert.

Picture Courtesy: Google Images

Koh-I-Noor

SDI -where creativity meets excellence

Technical Drawings

Article-6

Technical Drawings

Technical drawings are a means to communicate fine, detailed information about a piece of designed jewelry which helps in its construction. It is the link between the designer and the craftsman. With the help of technical drawing a craftsman is able to determine how the piece will turn out to be and what methods of manufacturing he has to apply in order to attain the desired result.

There are two basic categories of technical drawing:

Orthographic Representation

Perspective Drawing

In this post of Jewel Affair only orthographic representation will be covered.

Importance of Technical Drawings:

When one looks at the basic front view of a design it can be interpreted in different ways. For example if one looks at a circle drawn on paper it can be either interpreted to be a sphere or a flat disc. But if one provides the same circle with a technical view, it communicates exactly what has been thought of and hence, it avoids unnecessary confusion.

IMPORTANCE OF TECHNICAL DRAWINGS

Orthographic Representation:

It is a way of representing a three dimensional object in two dimensions. This is achieved by creating different views of an object. These views are:-

Top view: this view can be defined as the face of an object or how the product appears when viewed from top.

Front view: the elevation of the product is referred to as the front view.

Side view: this view usually shows the left or the right side of an object.

This helps in replicating the product with precision and accuracy. To create the orthographic representation actual dimensions of an object are used.

Construction of an Orthographic View:

CONSTRUCTION OF ORTHOGRAPHIC VIEW

Material required- pair of set squares, ruler, pencil, eraser and a drawing sheet.

With the help of your set squares draw the ‘x’ and ‘y’ axis. Mark 30 mm on all four quadrants. And then join the marked points to create a square. What we achieve here is a big square with four small squares inside. These small squares are called quadrants.

The outlines created are called the projectors and they are perpendicular to the faces of the object and parallel to each other.

The quadrants are marked with numbers.

RULE:

Never draw inside the quadrants. Drawing has to be done on the extended lines of quadrants 2, 3, and 4.

In quadrant 1 we draw an angle of 45° and extend the line outside the big square. Top view is represented by extension of quadrant 2. Front view by quadrant 3 and side view by quadrant 4.

Always take the measurements in millimeters and show the measurements always in the front and side views.

This is the basic guideline of an orthographic view.

Further illustrated here is the view of a flat band.

 

ORTHOGRAPHIC VIEW OF A FLAT BAND

Construction: Material required- pair of set squares, ruler, pencil, eraser, a drawing sheet and a compass.

Draw the basic guideline as explained above.

Measure the ring size or the finger size, the thickness of the shank the width of the band and outer size (ring size + thickness of the shank)

Extend the lines of quadrant 2 horizontally and vertically. Mark the width of the band on the ‘y’ axis (vertical) and the outer size on the ‘x’ axis (horizontal). Now, with the help of the set squares draw a rectangle with these measurements. This is the top view of the band.

Extend the lines of quadrant 2 corresponding to the outer size vertically downwards to quadrant 3. Mark the outer size on ‘x’ and ‘y’ axis and draw a square of this size. Using a compass to draw a circle of 9 mm radius, touching the four corners of the square. Also draw a smaller circle of 8 mm radius inside the 9 mm circle. This represents the elevation or the front view of the flat band.

To create the side view lines have to be extended both from top and front view.

From the top view extend the line which corresponds to the width horizontally until it meets the extended angle line created in quadrant one. From the point where it meets the angle line, extend the line vertically downwards.

From the front view extend lines corresponding to the outer width and lines corresponding to ring size horizontally towards quadrant 4. When the lines from both the front and top view meet the side view is automatically created.

One could also create cross sections in the front and side views to facilitate clear understanding of the design.

For this flat band, cross section of the side view is presented. To draw the same extend the lines of the side view vertically downwards. Using the same measurements create the same view as above. The only difference will be that the cross section will reveal the thickness of the shank.

Tip: try to imagine the flat band in your head and how it will look when it is cut.

Imagination is a powerful tool for a designer. One has to give it a right direction to achieve desired results. Similarly orthographic view is what will give one the direction to accomplish the pre-determined idea.