Power of Gemmology By Prachur Singhal

Geological Occurrence Gem stones are mainly inorganic solids obtained from the Earth. They belong largely to the mineral kingdom and have been formed by inorganic processes i.e. without the agency of organisms. This may be the reason why, in gemology or the gem trade, the term  stone  is colloquially used for any gem material whether organic or inorganic, natural or man-made. Mineral   An inorganic, homogeneous substance, formed in the Earth's crust, with a characteristic chemical composition and physical and optical properties which are constant within narrow limits. Example:  emerald ,  ruby ,  diamond  etc. Rock   An aggregate of two or more minerals. It may consist of a single component like marble ( calcite ), or may contain more than one mineral.  Lapis lazuli  is a rock which is made up of lazurite with (sometimes)  calcite  and / or  pyrite . Structure of the Earth The earth is a sphere made up of concentric layers. The outermost layer is a thin shell

Gemstone Treatments (Enhancement) Enhancement and treatments are done on gemstones to improve their  appearance, properties  and consequently their  value . This is generally practiced on lower grade goods so as to increase their salability. In actual terms, improvements in a gem material may be specifically related to improvement in Colour and / or Clarity and / or Phenomenon and / or Durability. In some cases a stone is subjected to more than one form of treatment. A number of  classifications  have been put forward by  ICA ,  GIA , CIBJO, jewelers associations in different countries etc. As yet no single classification is considered as a standard. The terms enhancement and / or treatment are used ambiguously by members of the trade, though there is a general concept that the acceptable ones such as oiling may be considered as an enhancement while glass fillings, irradiation etc. as a treatment. The technical concept remains that - whether you call it enhancement or treatme

Emerald/Emerald Doublet Figure 1. This 1.81 ct specimen was a natural emerald/emerald doublet. Photo by Claire Ito; field of view 10.5 mm. While various combinations of materials are used to form doublet gems, we seldom see doublets consisting of the same materials. Ruby/ruby doublets (Spring 1987 Lab Notes, pp. 47–48; Spring 1996 Lab Notes, p. 49) as well as a tourmaline/tourmaline doublet (Summer 1990 GNI, pp. 165–166) have been reported, but a doublet consisting of two sections of natural emerald has not been previously documented. GIA’s Tokyo laboratory recently examined a 1.81 ct transparent green octagonal step cut that measured approximately 7.22 × 6.71 × 5.55 mm (figure 1). Standard gemological testing indicated an SG of 2.71, with an RI of 1.572–1.580 on the crown and 1.570–1.578 on the pavilion. A chromium spectrum consistent with emerald was visible with a handheld spectroscope. Upon first glance, this stone appeared to be a natural Colombian emerald, but car

The Eduard Josef Gübelin Story:  T he Swiss gemologist Dr. Edward J. Gübelin (1913–2005) will be forever linked to the study of inclusions in gems. His work revolutionized gemology: As a result of his groundbreaking research and photomicrography, these internal features are now recognized for their diagnostic value, as indicators of a gem’s identity, geographic source, treated or untreated condition, and natural or synthetic origin.   This book, written by several family members, chronicles Edward Gübelin’s 65 years of pioneering research but also provides insight into his profound humanity. Even though the work of a research gemologist is often solitary, Dr. Gübelin touched thousands of lives through his prolific writings and photomicrographs, his extensive travels, the work of his laboratory, the educational organizations he helped establish, and the important gem collection he assembled.   Dr. Gübelin’s impact on my own career began in 1979. I was 22 years old

Large Blue and Colorless HPHT Synthetic Diamonds The technology for producing gem-quality synthetic diamonds is making rapid progress. In May 2016, GIA’s Hong Kong laboratory examined five large HPHT synthetic diamonds grown by New Diamond Technology (NDT) in St. Petersburg, Russia (table 1). Examination confirmed that all of them had the known characteristics of HPHT synthesis. Two of the synthetic diamonds were colored graded as Fancy Deep blue (figure 1). The 5.26 ct heart shape and the 5.27 ct emerald cut both surpassed the previous record for largest blue HPHT synthetic,  a 5.02 ct specimen reported very recently . Infrared absorption spectroscopy showed that both were type IIb, with strong absorption bands from boron impurity. We observed the typical color banding of HPHT synthetics, with more blue color concentrated in the {111} growth sector. Photoluminescence analysis at liquid nitrogen temperature with various laser excitations revealed no impurity-relate

About Raghunandan Prasad Padam Prakash Jewellers: Who We Are The house of Raghunandan Prasad Padam Prakash Jewellery was established in 1918 in Meerut. We are today a complete and one of the most respected Jewellery house celebrating 95 years of excellence jewellery, always innovating complementing the wonders of a woman's beauty though our ageless and timeless Raghunandan Prasad Prakash Jewellers tradition.  We have always been famous for our gorgeous jewellery which are perfect for Celebrating any major milestones in one's life – be it your wedding your Anniversary or birthday of your loved ones. Our jewellery styles and designs range from traditionally elegant and simple to highly intricate designs that would be appropriate for any formal event.  To provide the best possible value to our customers have been the ethos at Raghunandan Prasad Padam Prakash Jewellers, right from its inception. The is Why, much before introduction of hallmarking in year 1997.  All Diamond

Diamond Jewellery The 4 C's of diamond   1. Clarity:- When we speak of a Diamond's clarity we are referring to the presence of birthmarks or tiny inclusions on or within the stone. If you think about the incredible amount of heat and pressure it takes to create a Diamond, it's no surprise that many Diamonds have inclusions, scratches, blemishes and spots on their surface or inside. If other factors are equal then a flawless diamond is more expensive. Diamonds are graded for clarity from Internally Flawless to included.  2. Cut:- Cut unlocks the natural brilliance of Diamonds. It is perhaps the most important of the 4 Cs. For, the cut not only reflects the general outward appearance of the diamond such as round, emerald or pear shape, but it also gives it its reflective properties. Since a Diamond is only a reflector, a well shaped, excellent cut Diamond gives maximum brilliance as it reflects all the light entering from the front. An Excellent polish and symmetry maxim

Gold Jewellery What is 22 Karat gold Jewellery?   We use the term 22 Karat so often while buying Gold Jewellery but do we really know what 22 Karat means? Karat is the unit of the purity of Gold. This purity is expressed in terms of percentage also.  24 Karat gold = 100% pure gold.  1 Karat gold = 100/24 = 4.166%  Now we know that in 1 Karat there is 4.166% Gold, so to calculate the purity of any Karat of Gold just multiply that with 4.166. For example, if we want to know the percentage purity of 22 Karat Gold then, 4.166 x 22 = 91.67%. Which means that in 22 Karat Gold there's 91.67% pure Gold.  What is Hallmarking?   You can buy hallmarked jewellery with your eyes closed. It's that assuring. It's the ultimate certificate of purity for any jewellery. What's more, your Hallmarked jewellery would be evaluated at the marked level of purity anywhere. How is Hallmarking done? For Hallmarking the jewellery is sent to the Bureau of Indian Standard (BIS), authorized labor

Scientific Instruments Help Researchers Tell Gem Stories: The names of these instruments may sound cryptic, but to GIA researchers they are the tools that help unravel the mysteries of the gems. Researchers analyze and come to conclusions about the identity of a sample gem by comparing what they find to a database of the numerous gems GIA has examined over the years. They use their expertise and knowledge to look for the distinctive characteristics that reveal a gem’s identity. The information they gather and the instruments used to collect it can be categorized into light analysis, atomic structure analysis, chemical analysis and imaging. LIGHT ANALYSIS Spectroscopy analyzes the way light interacts with the gem. Researchers can identify a gem, and can often determine if it has been treated or is synthetic, by examining how it absorbs or transmits light. Visible Spectrophotometer A visible spectrophotometer shines a narrow beam of light through the ge

Diamond Diamond is the most precious of the gemstone. The word "Diamond" originally comes from the Greek word "Adams" which means "Unconquerable". Diamonds are formed by nature in the upper mantle of the earth’s crust. Crystallization took place millions and millions of years ago, under enormous pressure and at a very high temperature. Before being forced to the surface of the earth, they were stored in the upper mantle of the earth at a depth of 150-300km below the surface. The atoms in diamond are equidistant from one another. Graphite and diamond both are the forms of carbon but with highly diverse properties. Diamond is the purest crystalline transparent form of carbon whereas charcoal, soot and coke are non-transparent and non-crystalline impure form of carbon. Diamond is bad conductor of electricity. It is not surprising that rough diamonds are never completely free of impurities or irregularities in crystal structure. Growth of en

A Fantastic Display of Phase Changes in a Sapphire’s Fluid Inclusion n corundum of metamorphic origin, the presence of carbon dioxide (CO 2 ) fluid inclusions is a useful diagnostic indicator that no heat treatment has occurred; a gemologist simply has to cool the stone to below approximately 31.5°C to observe these inclusions (J.I. Koivula, “ Carbon dioxide fluid inclusions as proof of natural-colored corundum ,” Fall 1986  G&G , pp. 152–155). Even though this type of inclusion is considered commonplace in sapphires that form in a metamorphic environment, a spectacular example was recently witnessed in a Sri Lankan sapphire. When viewed correctly, the inclusion is revealed to be a negative crystal with a very tabular morphology (figure 1); for more on distinguishing negative crystals, see Fall 2009 Lab Notes, pp. 212–213. The negative crystal also contains a rather large graphite crystal. As the specimen’s temperature is lowered, the CO 2  trapped in the negative crys

Romancing the Source: Cambodia The romance of a colored gemstone arises from its beauty, the exotic qualities of its source’s location, the adventure leading to its discovery, and the stories of the people who seek it. These factors have united to create the allure of gemstones through the ages, and continue to do so even in modern times. Pailin, Cambodia, is located right next to Thailand, and this area has known more than its share of hardship. As a major battleground during the wars with the Khmer Rouge, the amount of civilian suffering is almost unimaginable. Today, there are still numerous reminders in the form of citizens, including miners, with legs lost to the Khmer Rouge mines that were planted all over the area. Drug-resistant malaria also plagues locals, especially miners working in the jungles. The rubies and sapphires brought to the surface by volcanoes are a source of income for this struggling area. Although production has decreased, hard-working individuals