Agate

A sapphire means blue in Greek. The blue goes from dark blue almost black to pale blue. The finest blue sapphires are a strong blue. The star sapphire is very valued. Sapphires of colors other than blue are always referred to with the color. There are pink sapphires, yellow sapphires, violet sapphires, green sapphires and clear sapphires. Today most sapphires are mined in Australia.
The sapphire was called the "Stone of Destiny". Sapphires contribute to mental clarity and perception. They can promote financial rewards.
The sapphire is the symbol of heaven and joyful devotion to God.
Sapphire is associated with Aquarius, Virgo, Libra and Capricorn. It is the birthstone of September and has been the birthstone of April. Sapphire is the symbol of Saturn (dark blue) and Venus (light blue).

Agates of volcanic origin contain a range of microcrystalline silica minerals; cryptocrystalline silica, chalcedony and quartz, arranged in concentric bands. Although abundant worldwide, little is known about the genesis of the characteristic banding patterns. Researchers disagree whether the bands result by precipitation from siliceous hydrothermal influxes or by in situ crystallisation of a silica gel. The study combines the use of an array of techniques, including electron backscatter diffraction (EBSD), cathodoluminescene (CL) and Fourier Transform infrared (FT-IR) spectroscopy, to characterise the silica minerals present and investigate the relationships between them in the banding arrangement. Microstructural and compositional (trace element, water content) observations reveal the bands form by discrete siliceous fluid influxes. Within these individual bands a gradual change in mineralogy analogous to silica diagenesis is observed; cryptocrystalline silica chalcedony quartz. The change is reflected in the degree of crystallinity, trace element (e.g. iron) distribution and water content. The proposed band growth model can account for the observed changes in composition with respect to the silica minerals present. Crystallographic orientation data reveals a strong a axes lineation which is present throughout the sample, suggesting a universal control on agate growth.

Menurut model karakteristik perusahaan yag dikembangkan oleh J.Richard Hackman dan Greg Oldham, berdasar 5 core job dimension, PT. Agate International memiliki:
Skill Variety : didalam pembuatan game , PT. Agate International memiliki beberapa divisi yang melakukan beberapa aktivitas yang berbeda, didalam aktivitas seperti pembuatan model karakter banyak pegawai yang memiliki skill di bidang ilustrasi dan gambar, pembuatan game platform dikerjakan oleh orang-orang yang memiliki kemampuan pemrograman unggul, karna itu  dibutuhkan skill dan kemampuan individu di divisi masing yang berbeda-beda untuk menciptakan sebuah karya atau proyek game.
Task Variety : setiap divisi memiliki tugas atau proyek masing-masing yang harus disempurnakan. Misalkan para programmer di PT. Agate International harus dapat membuat sebuah platform game bertipe RPG, yang didalamnya harus dimuat 3 jenis karakter dan 3 jenis senjata, selain itu penempatan ruang NPC dan lain sebagainya. Mereka membuat platform game secara lengkap dan rinci, agar nantinya akan bias dimasukan design karakter/item dari para illustrator PT. Agate International, sehingga sebuah game pun dapat tercipta.

Bu çalışmada, Çubuk (Ankara) ilçesinde bulunan andezitik ve riyolitik birimlerde köşe ve kanal dolgusu olarak gelişen ve bunun dışında içinde kendine özgü çubuksu kristalleri bulunan Çubuk agatlarının karakterizasyonu ve süstaşı olarak kullanılabilirliğinin araştırılması amaçlanmıştır. Bu kapsamda agat numuneleri üzerinde bir dizi karakterizasyon (XRD, SEM, FTIR, Mineralojik ve Petrografik inceleme, kimyasal ve gemolojik özellikleri) çalışması yapılmıştır. Petrografik incelemeler agatların lifsi kalsedon bantlarının tekrarlanmasıyla karakteristik bir görünüm kazandıklarını göstermektedir. SEM çalışmaları kalsedon bantlarının farklı zamanlarda çekilen kuvars polimorfları olduğunu belirtmektedir. XRD ve FTIR çalışmaları agatların silis polimorflarından opal- CT, kalsedon, kristobalit ve kuvarstan oluştuğunu göstermektedir. Yapılan gemolojik çalışmalar agatların mohs sertliğinin 6,5, özgül ağırlığının 2.61 g/cm3, kırılma indisinin 1.545 ve su emme oranının % 0,4 olduğu belirlenmiştir. Çalışma sonunda, agattan üretilebilecek dekoratif ürünler, özellikle süstaşı işleme makineleri ile yapılabilecek objelerin (kadeh, mumluk, havan) işlenebilirliği öngörülmüş, bazı dekoratif ürünlerin kolaylıkla üretilebileceği belirlenmiştir.

The contribution presented is part of research work aimed at specifically and thoroughly interpreting and analysing a group of related decorations on vessels made of glass and (ornamental and semiprecious) stone. The pieces included illustrate cases of skeuomorphism supported by archaeology, ancient literary texts, archaeometry and the evidence of a developed and uninterrupted technological, functional and comercial heritage going back to the 23rd century B.C., when the most ancient pieces made of glass are documented, up to the present day. Particular attention is paid to objects from the Roman period housed at the Museo Arqueológico Nacional such as glass bowls and unguentaria, the agate vessel from Merida or the diatreta found in Tiermes, and also from earlier periods, such as the jug from Aliseda. Particular value is attached to all these objects in terms of their worth, peculiarity, beauty or artistic quality which are analysed and interpreted following the parameters of the research work in progress.

Agate samples of acidic, intermediate and basic volcanics from 18 localities around the world and of different age
ŽPrecambrian to Tertiary. were studied by trace element and stable isotope analysis to provide information about the process
of agate formation and the origin of mineral-forming fluids. Trace element data are similar for agates from acidic and basic
volcanics. The general chondrite-normalized REE distribution pattern is characterized by a slope from La to Lu with
enriched LREE and a positive Eu anomaly in some samples. The similarity in the shape of the REE patterns between agates
and the parent volcanic rocks suggests that the elements are mobilized by circulating fluids during syn- and postvolcanic
alteration of the volcanic wall rocks. Observed positive Eu anomalies in agates probably originate from feldspar alteration.
Ž 18 Deuterium and oxygen isotope analyses of agates and associated quartz incrustations d D: y44‰ to y130‰; d O:
q16.4‰ to 33.4‰. reveal variations in isotopic composition between samples of different localities but also within single
agate samples Žup to 10‰ for d18O.. In general, oxygen isotope compositions become heavier as volcanic host rocks grow
more acidic. Furthermore, agates have higher d18O values than associated quartz incrustations. Variations within single agate
samples can be explained either by kinetic effects during isotope fractionation Že.g., the formation of agate from a
. 18 noncrystalline precursor or by mixing processes of meteoric and magmatic fluids. Remarkably high d O values of the
Ž . 18 parent volcanic rocks up toq19.5‰ suggest that the circulation of O enriched hydrothermal fluids originated from
heated meteoric water andror residual magmatic fluids. This conclusion is supported by d13C and d18O data of paragenetic
calcite. The temperature of agate formation was calculated for different fluid compositions, and they indicate a temperature
range of ca. 50C to 250C.

Over recent decades, numerous studies have highlighted the importance of opal, chalcedony and quartz varieties, chiefly in volcanic, but also in metamorphic and sedimentary environments. The focus is to define accurately their structures, composition and properties, as well as to identify the factors controlling the formation and the ageing ofdifferent forms of silica. In the field ofarchaeological sciences efficient discriminants are the bases from which the origin and provenance of materials may be traced. Substantial efforts were made in the attempt to combine geochemical, mineralogical, petrographic and geological features with archaeological and archaeometric information. However the results show that data integration is complicated, and several unanswered questions remain. On the one hand, archaeological research has focused on technological and ethnographic aspects, mainly concerning use-wear and heat-treatment studies. Mineralogical characterization has often been limited to the identification of the material, frequently by Raman microspectroscopy alone. On the other hand, the Earth sciences have provided basic mineralogical, crystal-chemical and geological knowledge, but failed to provide a systematic data collection of sources and their geochemistry. As a consequence, large gaps persist in the identification of archaeological opals, chalcedonies and quartz varieties, and in the geographic mapping of possible sources. In this context, the present review aims to summarize the current academic debate on such issues, possibly to encourage further work in the field. After a brief introduction to terminology, the structure of opals, their colours and properties are discussed, followed by an introduction to silica dissolution/precipitation and opal-formation processes. The next section reviews the information available on use of opals and provenance from historical sources, mainly Pliny the Elder, followed by a short list of ancient and modern opal supply areas, together with a (necessarily incomplete) summary of the geological and geochemical information. The discussion then encompasses chalcedony, agate and chalcedony varieties (carnelian, sard, onyx, sardonyx, chrysoprase, Cr-chalcedony, ‘gem silica’ or ‘chrysocolla chalcedony’ and heliotrope), following the same scheme as was adopted for opals. Terminology, distinguishing features, formation conditions, information derived from Pliny’s books, past and current supply areas and, finally, archaeometric provenance issues are addressed for each type of material. As for chalcedony, a comprehensive note on moganite has been included. The nextsection focuses onchert, flintand jasper. Given the large amountof materials available on this topic, the present review must necessarily be considered introductory and partial. The discussion aims to provide useful indications on how to distinguish chert from flint and chert from jasper; secondly, the information provided by Pliny and the archaeometric state of the art on these materials is reviewed.
The last section examines quartz varieties: hyaline quartz (rock crystal), milky quartz, smoky quartz, rose and pink quartz, amethyst, citrine, prasiolite and blue quartz. An exhaustive mineralogical discussion on quartz is beyond the scope of this review; conversely a review of the historical information is provided, together with a brief list of major supply areas, a summary of the archaeometric studies performed on these materials, as well as an indication of the geological literature which can be used proficiently for provenance studies.

Uno studio sulla Murrha, forse il materiale naturale prezioso più discusso della storia dell’arte antica.
Tema trattato da Properzio e Giovenale, descritto con precisione da Plinio nel XXXVII libro della Naturalis Historia, si sono succedute nei secoli le interpretazioni più varie per il riconoscimento della pietra preziosa che costituiva i famosi, costosissimi e ambitissimi “Murrina Vasa”.

Si è creduta essere marmo, alabastro, fluorite, vetro, porcellana, conchiglia, ambra, mirra, diaspro, ecc.

L’autore con una attenta disamina dei testi antichi e un confronto con i materiali più preziosi dell’antichità, conservati nei vari musei e nelle raccolte d’Europa, giunge ad una chiara e inequivocabile conclusione che ha tutti i riscontri storici, filologici e tecnici.
Si è riunito per la prima volta un repertorio di più di 300 esemplari di vasi murrini nelle collezioni pubbliche e private di tutto il mondo.

Characterization of the Agates Collected from Çubuk Region of Turkey and Processability of these Agates as Ornamental Stone
ÖZET Bu çalışmada, Çubuk (Ankara) ilçesinde bulunan andezitik ve riyolitik birimlerde köşe ve kanal dolgusu olarak gelişen ve bunun dışında içinde kendine özgü çubuksu kristalleri bulunan Çubuk agatlarının karakterizasyonu ve süstaşı olarak kullanılabilirliğinin araştırılması amaçlanmıştır. Bu kapsamda agat numuneleri üzerinde bir dizi karakterizasyon (XRD, SEM, FTIR, Mineralojik ve Petrografik inceleme, kimyasal ve gemolojik özellikleri) çalışması yapılmıştır. Petrografik incelemeler agatların lifsi kalsedon bantlarının tekrarlanmasıyla karakteristik bir görünüm kazandıklarını göstermektedir. SEM çalışmaları kalsedon bantlarının farklı zamanlarda çekilen kuvars polimorfları olduğunu belirtmektedir. XRD ve FTIR çalışmaları agatların silis polimorflarından opal- CT, kalsedon, kristobalit ve kuvarstan oluştuğunu göstermektedir. Yapılan gemolojik çalışmalar agatların mohs sertliğinin 6,5, özgül ağırlığının 2.61 g/cm3, kırılma indisinin 1.545 ve su emme oranının % 0,4 olduğu belirlenmiştir. Çalışma sonunda, agattan üretilebilecek dekoratif ürünler, özellikle süstaşı işleme makineleri ile yapılabilecek objelerin (kadeh, mumluk, havan) işlenebilirliği öngörülmüş, bazı dekoratif ürünlerin kolaylıkla üretilebileceği belirlenmiştir.

ABSTRACT This study aimed charactarization of the agates -which develop as edge and channel filling in andesitic and rhyolitic units and which have a unique, twiggy cyrstaline structure- collected from Çubuk Region of Ankara Province, Turkey. Present study also searched processability of these agates as ornamental stones. In this scope, a set of characterization analysis (mineralogical and petrographic analyses, XRD, SEM, FTIR, chemical and megological characteristics) were made on the agate samples. Petrographic analysis showed that agates had an appereance characterized by repetation of thready chalcedony bands; SEM analysis that chalcedony bands had quartz polymorphs taken at different times; XRD and FTIR analyses that agates consisted of the silica polymorphs of opal-CT, chalcedony, cristobalite and quartz; and gemological analysis that hardness value was 6.5, specific weight was 2.61g/cm3, refractive index was 1.545 and water absoprtion rate was 0.4% for the agate samples. The results of the present study suggest that the decorative products, particularly the objects carved via ornimental stone lathes (such as sphere, candlestick, mortar and jewelry products), to be produced from agates are processable and that there are some decorative products which can be produced from agates easily.

Here we present a database of responses by South African agate and chalcedony to heat treatment. This will assist analyses of heated stone tools not only in South African archaeological sites, but wherever heated agate and chalcedony pieces were knapped. The minerals are abundant worldwide. To replicate potential heating methods during the Stone Age we placed some minerals in a wood fire, some under coals, and others were buried in sediments beneath fires. Thermal responses include lustrous flaked surfaces, pot lid fractures, semi-circular internal fractures, rough internal surfaces, and crazing. Aerobic heating is implied by pot lid fractures. To explain the thermal responses we analyzed the minerals using X-ray fluorescence, Raman spectroscopy, and carbon and sulfur analyses. Our chalcedony contains more water and impurities than agate, making it more vulnerable to thermal damage. Our method of combining field experiments with chemical analyses has global applications even though we expect that mineral components of agate and chalcedony will vary slightly in different parts of the world.

South African basalt-hosted chalcedonies provided an ideal case study, to (a) achieve information about the origin of mineral-forming fluids, the process of chalcedony formation and weathering alteration and (b) to verify if the geochemical and micro-textural characterization of chalcedony allowed multiple provenances to be distinguished. For the first time, Drakensberg chalcedonies from the Karoo Jurassic basalts and Windsorton chalcedonies from the alluvial environment of the Vaal River (traversing the Allanridge basaltic-andesitic lavas) were investigated by optical microscopy, laser ablation inductively coupled plasma mass spectroscopy and isotope ratio mass spectrometry (16 O, 18 O). The results showed that the compositional differences observed in Drakensberg and Windsorton chalcedonies could not be explained by changes in host rocks composition. The tholeiitic basaltic-andesitic lavas of the Allanridge Formation (Pniel Group, comparison term for Windsorton samples) and the tholeiitic basaltic-andesitic lavas of the Golden Gate Unit (Drakensberg Group, comparison term for Drakensberg specimens) proved to be very similar, also in terms of alteration degree. Conversely, both geochemical and oxygen isotope compositions clearly supported a relatively low temperature, hydrothermal origin for all the investigated chalcedonies, further indicating that differences mostly occurred during their formation (fluid circulation). Moreover, several characteristics suggested deposition in non-equilibrium conditions, although oxidizing conditions were most likely. Weathering processes were effective in the alluvial environment only, leading to a wider compositional heterogeneity of Windsorton chalcedonies with respect to Drakensberg samples. Lastly, a correlation between color and chromophores (Fe and Mn) amounts was lacking while a correlation between the geochemical composition and the texture was clearly observed in several specimens.

This work aims to study the treatment of a dye bearing effluent from an agate-processing plant by
sodium hypochlorite (NaClO) oxidation. The work includes effluent characterisation, chemical
oxidation experiments and evaluation of degradation products by Gas Chromatography coupled to
Mass Spectroscopy/Ion Trap (GC/MS/IT). The effluent presents a very intense colour (kmaxc550
nm), low surface tension and some organic content. Colour removal can be carried out in a few
minutes using 1.3 ml/l of NaClO at pH 7.0. Organic dyes are not completely oxidised by NaClO and
many degraded compounds were found in the treated effluent, including organochlorides. The use of
chlorine in the effluent treatment is discussed in terms of pollutants degradation and environmental
hazards.

Abstract: A relatively recently known occurrence of silica mineralization from the region of village Devintzi, Kardzhali district, is studied. It outcrops in linear zones and concentric formations, which in their central parts are generally made of carbonate materials, and to the periphery – from colorful striped SiO2-phases including carnelian. SiO2-phases are represented mainly by chalcedony and in minor quantity by quartz, tridymite, quartzine and opal. Three morphological types of chalcedony are established – spherulitic, fine granular and radial fibrous chalcedony. Tridymite and celadonite are defined using XRD.

A large embankment slope with domed shape, in the western part of the studied occurence, is surmised to be with man-made origin, related to the ancient episodic extraction of raw agate suitable for making jewelry and especially glyptics.


Резюме: Изследвано е сравнително отскоро известно проявление на силикатна минерализация от района на с. Девинци, Кърджалийско. То се разкрива във вид на линейни зони и гнезда с пъстроцветени опали и жили, които в централните части обикновено са изградени от карбонатен материал, а към периферията – от разноцветни ивичести SiO2 – фази в т.ч. карнеол. SiO2-фази са представени основно от халцедон и в подчинено количество – от кварц, тридимит, кварцин и опал. Отделени са три морфоложки типа халцедон – халцедонови сферолити, микрозърнест халцедон и параболично влакнест халцедон. Рентгеноструктурно са установени тридимит и селадонит.

В западната си част проявлението представлява голям склонов насип с куполовидна форма, за който се допуска, че е възможен техногенен произход, свързан с воден в древността епизодичен добив на ахатова суровина, годна за изработване на ювелирни изделия от тип глиптика.

The coastal sites of the UAE and the Sultanate of Oman in the sixth-fifth millennia BCE share a number of features in their material culture. In addition to lithic techniques, the populations shared particular technologies, such as architecture using load-bearing pots or the production of specific fishing material and ornaments in shell and mother-of-pearl. This corresponds to populations that were already Neolithic, with domestic animals and practising intensive fishing, which was sometimes specialised. Is it possible at this stage in our understanding, to assert that this assemblage is both well differentiated from those of Qatar and the northern Arabian Gulf and culturally homogeneous? Some answers are provided in this note.

The Jebel al-Ma'taradh and its surroundings contain exceptional deposits of lithic raw materials, including flint and chert, but especially chalcedony, agate, carnelian, and chrysoprase. These deposits were intensively exploited during the Neolithic, and some of the artefacts produced entered the trade network that included settlements on the coast and inland, sometimes as far as 300 km. During earlier periods, probably as early as the Pleistocene, only flint was used. Between the sixth and the fourth millennia, carnelian and agate were exploited to make beads, which are found in the necropolises and settlements of the UAE.

The Jebel al-Ma'taradh and its surroundings contain exceptional deposits of lithic raw materials, including flint and chert, but especially chalcedony, agate, carnelian, and chrysoprase. These deposits were intensively exploited during the Neolithic, and some of the artefacts produced entered the trade network that included settlements on the coast and inland, sometimes as far as 300 km. During earlier periods, probably as early as the Pleistocene, only flint was used. Between the sixth and the fourth millennia, carnelian and agate were exploited to make beads, which are found in the necropolises and settlements of the UAE.

The Cheshme Shoor area is located in northeast of Qom which is a part of central Iran geo-structural zone. The rocks of the area are mainly volcanic rocks that include Eocene acidic tuffs and ignim-brites. Different types of agate, jasper and amethyst formed as secondary cavity filling deposits in variety of colors and shapes in the area. In this paper, chemical treatments by different chemicals with heating methods in 15 different procedures have been conducted on one agate sample of the study area which has been divided into smaller pieces by milling. Dyeing with these methods has been done in blue, yellow and green colors. Excellent results have been achieved in 9 processes, significant but not expected results have been illustrated in 4 processes and 2 processes have been represented no changes. Produced colors have had a natural and light color which makes them more desirable to the consumers but totally these dyeing processes illustrate that concentration of the solution is effective in coloring and solutions with more concentrations produce stronger color.

The Cheshme Shoor area is located in northeast of Qom which is a part of central Iran geo-structural zone. The rocks of the area are mainly volcanic rocks that include Eocene acidic tuffs and ignimbrites. Different types of agate, jasper and amethyst formed as secondary cavity filling deposits in variety of colors and shapes in the area. In this paper, chemical treatments by different chemicals with heating methods in 15 different procedures have been conducted on one agate sample of the study area which has been divided into smaller pieces by milling. Dyeing with these methods has been done in blue, yellow and green colors. Excellent results have been achieved in 9 processes, significant but not expected results have been illustrated in 4 processes and 2 processes have been represented no changes. Produced colors have had a natural and light color which makes them more desirable to the consumers but totally these dyeing processes illustrate that concentration of the solution is effective in coloring and solutions with more concentrations produce stronger color.

Banded chalcedony, or agate, was appreciated for its high aesthetic quality by the rulers of the ancient Near East from the end of the 3rd millennium BC onwards. These stones are rare at Ugarit in the late Bronze Age. This study presents seventeen artefacts, of which fifteen were previously unpublished. These objects are mostly small and highly variable in typology: a cylindrical bead, a plano-convex discoidal bead, a cylinder, five " eyes " , an element in the form of a crescent, two " beads " or " weights " in duk form, two discs of which one has an astral decoration. The corpus also includes a " knob " and vessels, among which is an exceptional pyxis in siliceous breccia. These discoveries come from different loci of the royal palace. As the use of banded chalcedony outside the palace sector was very rare, we advance the theory that these stones were at Ugarit a favoured " royal material " , on a par with others, such as elephant ivory. We emphasize moreover the fact that certain pieces appear to illustrate links with the east of the Levant. Le mobilier du Palais royal d'Ougarit

Gemstones have been used throughout ancient history in various kinds of rituals and beliefs. From spiritual applications to therapeutic values, gemstones are still highly regarded in modern times. We hope that the following information compiled here will serve as a good reference for people looking for the meanings behind different gemstones and their associated properties.