Gemology
Gemology is the branch of mineralogy and geology dedicated to the study, identification, analysis and evaluation of precious stones or gems. A central task of gemology is to establish rigorous methods and procedures available to distinguish natural gems from their imitations and synthetic versions. These procedures include measurements made with different instruments and apparatus (for example, crystallographic and photometric measurements, microscopy, spectroscopy, X-ray diffraction analysis, etc.). It is, therefore, a scientific discipline that does not bears no relation to esoteric practices that assign meanings or supposed therapeutic properties to gems.
Due to the value of the pieces studied, he dispenses with those mineralogical methods that require the extraction of samples and uses only those procedures that preserve them intact.
The gemologist must know several disciplines such as: crystallography, optics, mathematics, crystallochemistry, analytical chemistry, synthesis and imitation of gems, among others.
The composition, physical properties, origin and deposits, the treatments of diverse nature, the types of cut that enhance the beauty of the gems, the synthetic minerals and characteristics as well as the properties of these materials that imitate the gems are studied. natural gems. Some of the frequent applications are appraisal and expertise.
History
The use of gem minerals is a phenomenon that appeared very early in the history of mankind. Since very remote times, human beings have sought to have in their possession the largest, brightest, purest and rarest specimens to adorn and adorn themselves, for aesthetic, ritual or religious purposes.
In the most primitive human associations, their use could respond to the need to stand out from others, with pearl, turquoise, shell or ivory necklaces, to mark belonging to a specific group or a social function within it. In all subsequent civilizations, it is primarily power and wealth that is manifested through the ownership of metallic ores and gems.
The first indications of the use of a material as a drilled gem date back 100,000 years, with the species Nassarius krausianus in South Africa. Kings and emperors have possessed the best pieces of their peoples, given as favors or tributes and the work carried out has been improved each time, refining the technique in all parts of the world.
Depending on the tastes and materials of each geographical area, we can find organic gems, transparent, translucent or opaque minerals. Man has always used any mineral with a certain beauty and hardness to decorate his objects both in life and in death. Many cultures like the Egyptian buried their aristocrats, important and wealthy people with treasures and these were directly proportional to the greatness of the person in life.
The oldest known scientific texts are the Egyptian recipe books for making mineral imitations (Stockholm and Leyden papyri) dating from the 1st and 4th centuries, but they are known to be copies of other Egyptian texts. The most characteristic precious stone of the Egyptians was turquoise already 4000 years ago. Jade was used by oriental cultures and more specifically by China for more than 5,000 years. Used in numerous objects, both religious and secular materials and of which we have some exceptional samples thanks to archaeological findings.
Thales of Miletus (600 AD) discovered in Greek culture the static electricity property of amber. Also in the Greek culture, a classification of minerals was carried out according to their color and in addition to texts classifying the gems referencing heating and mounting techniques to improve their appearance.
In the Middle Ages and the Renaissance, treatises appeared on the use of minerals for therapeutic treatments by alchemists, relating them to magical properties that were more or less adjusted to reality.
In Spain one of the most outstanding lapidaries was that of Alfonso X of Castilla “el Sabio” (1278), he described the nature of stones and their properties derived from the constellations by which they are governed.
Other notable works from the 16th century:
- Erasmus Stella (1517) Interpretamenti Gemmarum Libellus.
- Gaspar de Morales (1598) Of the wonderful virtues and properties of the precious stones.
- Anselmo Boecio (1609) Gemmarum et lapidum History.
- Thomas Nicols (1652) Lapidary or History of Precious Stones.
Special mention must be made of Arabic literature on gems that deserves a separate topic with writers such as Al Kindi, Al Biruni, Al Razi, Al Rumi.
They have been essential for the economy and the progress of civilizations and currency. They have been the cause of many greed disputes between neighboring towns and have provoked wars over these treasures. At present they are essential for technological progress and thanks to the production of synthetic gems, electronic components such as chips are made, improving telecommunications, industrial abrasives, etc.
Scientific aspects
In mineralogy, an inclusion is any material trapped within a rock or mineral and they are determinative for its identification in almost all occasions. They tell us how their genesis was, when and if they are natural or synthetic.
Gemology includes many aspects developed in multiple ways throughout history. Deposits have historically been found by chance and scientific knowledge has been given after their exploitation.
Europe bought precious stones from distant countries, the data of these deposits were reported by travelers and scientists in numerous documents. They alluded to legends such as the case of diamonds, about which it was said that they lay in inaccessible valleys and in order to capture them they used birds to later collect them more easily. An equally important true story was made by Marco Polo collected by Tavernier (1675) on his trip to Turkey, Persia and India, where a multitude of gems were described and also the Indian mines of Golconda from which all of them came.
Physical properties of gems
For a piece to qualify as a gem, it must have the following three qualities:
- beauty
- durability
- Rarity
In its identification and evaluation, the properties of color, brightness and purity also play an important role.
Classical Gemology
Characterized by the study of the optical properties of minerals. On this knowledge a book was made in 1978 with the work of Kurt Nassau. Currently, color is specified by means of chromatic concordances. The knowledge of physical, optical, and beauty properties of gems has allowed applying scientific criteria to improve their appearance.
The best-known example is the brilliant-shaped diamond cut design. The round diamond cut was developed by Marcel Tolkowsky in 1919. With this type of cut, it is achieved in a mathematically calculated way to balance the brilliance and fire of this gem from its optical properties. Calculated so that any incoming light ray from the corona (top) is reflected and returned to the observer, maximizing brightness. At the same time, the departure angle produces the dispersion of color, causing what is called fire.
The evolution of the cut has gone parallel to the scientific and technical development and thus it has gone from simply polished forms to the current faceted cut, to the brilliant type and to computer design where the results can be seen before carving the copies.
Gemology, law and economics
Gemologists specializing in appraisals must be familiar with European regulations, appraiser-auditor relationship, valuation bases, special property values, special purpose valuations, non-market estimates and valuations, specific securities law and practice, prosecution law applicable.
Titration
In Spain
The corresponding Gemology studies are Higher Studies not attached to the general regime. Students who pass these studies obtain the title of Gemologist in the corresponding specialty, which is equivalent, for all purposes, to the title of University Diploma + Specialist.
These courses consist of three academic courses, two general and one specialization.
- Finalized Two first courses and prior overcoming a training test is obtained Diploma of Gemologist.
- Overcoming specialization course, overcoming the corresponding training test and reading the tesine is obtained Specialist Gemologist Diploma in Diamond.
Passing a Postgraduate course means obtaining the Postgraduate Degree in the corresponding Specialty.
The Gemology Diplomas of the University, enable the professional practice of Gemologist and Jeweler throughout the Spanish State, allow homologation and registration.
International
Internationally, the Gemological Institute of America (GIA) is the largest gemological campus and laboratory in the world since its founding in 1931. The most important gems in the history of gemology have been analyzed here and have played an important role in establishing the bases of this discipline, as well as norms and criteria of international validity, for example, the famous "4 Cs" (cut, color, clarity, carat) as criteria for determining the beauty and quality of diamonds. The institute is commonly called the "Harvard of Gemology".
Other world-renowned campuses and laboratories include "HRD" and "EGL", in Europe.
In summary, the gemologist is the qualified professional who can determine that a gem is such, through laboratory explorations and his experience, and he is the only one who can certify a gem.
Regarding the professional field of gemologists, we can highlight jewelry stores, workshops, gemological laboratories, as well as judicial expertise, customs, specialized public order forces, auction centers and museums, it is imposed in the sectors of the culture, art and luxury market.
Read also
- Mining