Gemology

Copyright 2009, Society of Petroleum Engineers This paper was prepared for presentation at the 2009 SPE/EAGE Reservoir Characterization and Simulation Conference held in Abu Dhabi, UAE, 19–21 October 2009. This paper was selected for presentation by an SPE ...

سبک های جواهرات قرن بیستم یک انقلاب دل¬انگیزی را نشان می¬دهد. این سبک ¬ها به نام هنر جدید Art nouveau، Edwardian (یا Garland) ، Art deco و Retro که هریک در دوره خاصی بکار می¬رفته و هریک مدل¬های مخصوص خود را دارند.
در طول دهه اول قرن بیستم، صنعت جواهرسازی دوباره احیاء شده که به دلیل کشف منابع جدید سنگهای قیمتی، برپایی کارخانجات جدید و روش ها و تکنیک¬های تراش جواهر بود. قوانین اجتماعی نیز تغییر کرد و قیمت جواهرات به گونه¬ای بود که عموم مردم دسترسی و توانایی خرید آنرا داشتند. تغییر نقش زنان در جامعه و بالارفتن سطح زندگی طبقه متوسط میزان تقاضا را افزایش داد. در نتیجه در پاسخ به این تغییرات در مدل و طرح¬های جواهرات توسط سازندگان ایجاد شد.
در نیمه اول قرن بیستم چندین مدل اصلی جواهرات بوجود آمد که برخی با حرکت¬های هنری همگام بودند و برخی از دوران کوتاه جنگ تاثیر گرفتند و یک اثر بسیار درخشانی را بجای گذاشتند.

There are a few trade names and expressions that are not exactly accurate if we look at them in a very strict way. However, written or verbal tradition have given them a wide visibility and usage among both professionals and the general public, and many have became part of the trade’s vernacular and nomenclature. Here are a few examples.

Hydrothermal synthetic emeralds manufactured by Biron, Regency and Tairus have been distinguished from natural and synthetic emeralds using chemical analysis and infrared (IR) spectroscopy. Polarized IR spectra have been obtained from plates. Hydrothermal synthetic emeralds possess infrared absorption features not present in natural emeralds, and these features have been investigated. We infer that the system of five narrow bands in the 3000-2600 cm-1 region is related to the dimer formation of HCl molecules, which have been incorporated in the channels parallel to the c-axis during growth of Biron and Regency emeralds. In Regency emeralds, a double band with maximum at 3295 and shoulder near 3232 cm-1 and a broad band between 3000 and 2500 cm-1 are attributed to hydrogen- bonded NH4 + ions. In Russian hydrothermal synthetic emeralds the strong infrared spectral features related to molecular water are generally similar to those of some natural emeralds but there are also broad bands due to Ni2+ and Cu2+ ions in the near-infrared regions which enable one to distinguish Russian hydrothermal synthetic from natural emeralds. Other bands unrelated to water in hydrothermal synthetic emeralds are also discussed.

What has natural history done for physics? The eighteenth century is an important source of answers to this question, since it witnessed the emergence of experimental physics and systematic natural history as distinct branches of science. Much existing literature suggests that these two traditions were opposed in the eighteenth century or that they rarely made contact. The main aim of this dissertation is to show that natural history made an important contribution to the experimental method of the French scientist Charles-François de Cisternay Dufay (1698–1739). This contribution took the form of systematic experimental history. To do systematic experimental history is to apply the same experimental operation to a large number of animal, plant or mineral species, with the aim of comparing the outcomes of these trials. An analysis of Dufay’s articles and correspondence shows that he possessed a large gem collection and that he was in contact with some of the most prolific collectors of his day. His systematic experimental history of gems informed his pioneering papers on electricity, luminescence and double refraction. In this form natural history helped him to discover new phenomena, generalise known phenomena, optimise known phenomena, and discern taxonomic rules, ie. rules expressing contrasts between the observable behaviour of different kinds of material. Dufay’s rules about the electrical behaviour of conductors and non-conductors are of particular interest. These rules were the basis for an absorption theory of electrics that sheds new light on Dufay’s electrical research and on that of his immediate French successors. These reinterpretations of Dufay’s experimental papers are supported by two further claims. The first is that there was a continuous tradition of systematic experimental history at the Académie Royale des sciences in the seventy years before Dufay began his electrical research. The second is that Dufay’s relationship with René Réaumur, the leading naturalist in France at the time, was richer than historians have supposed. This study opens up new lines of research on the role of materials in the qualitative physics of the eighteenth century, the role of naturalists in the quantification of physics around 1800, and the interaction between physics and mineralogy at the Jardin du Roi and, in the nineteenth century, at the Muséum national d’histoire naturelle.

In an industry where products, in this case gem materials, are traded and valued by their weight, it is critical to fully understand the multitude of units out there, especially if interpreting antique or foreign descriptions, and how weights should be expressed according to the best trade practices.

Ebû Reyhân Muhammed bin Ahmed el-Bîrûnî (973-1061)
Biyografi ve Arapça orijinalinden tercüme:
Dr. Emine Sonnur Özcan, Türk Tarih Kurumu Yayınları, Ankara 2017.

ÖNSÖZ
Doğumunun 1040. yılını idrak ettiğimiz 2014 yılında, Ebû’r-Reyhân Muhammed bin Ahmed el-Bîrûnî ’nin, Kitâbu’l-Cemâhir fî Ma‘rifeti’l-Cevâhir isimli eserini geç de olsa Türkçe’ye kazandırmaktan onur duyduğumuzu söylemeliyiz.
Yalnızca Ortaçağların değil, tüm zamanların en büyük âlimlerinin biri olan Üstad Ebu’r-Reyhân’ın yüz elli civarındaki eserinden günümüze ulaşan yirmi iki kadarı arasından Türkçe’ye tercüme etmek üzere seçtiğimiz el-Cevâhir, sadece bir mineraloji kitabı değildir. Kozmolojiden astronomiye, kimyadan fiziğe, edebiyattan tarihe, Ortaçağların pek çok  ilmî, moral ve sanatsal alanına ilişkin eşsiz bilgiler veren bu eserin, hemen her okurun kulağına fısıldayacak bir sözü var, diyebiliriz.
Tercümede kullandığımız temel nüsha, el-Cevâhîr’in Kayseri, Râşid Efendi Kü-tüphânesi’nde bulunan, 596-553.1 numaralı ve h.626/m. 1229 tarihli elyazmasıdır. Bu nüshada okuyamadığımız ya da anlayamadığımız yerlerde, eserin Topkapı Sarayı Kütüphanesi, No: 2047’de bulunan yazmasına dayalı Arapça baskısı (el-Cemâhir fî’l-Cevâhir, Tahkîk: Yûsuf el-Hâdî, Kültür Bakanlığı, Tahran 1990) ve Fritz  Krenkow’un yine aynı nüshaya dayalı olarak 1936’da yayımladığı ilk Arapça baskısının, merhum Pakistanlı âlim Hakim Muhammed Said tarafından yapılan İngilizce tercümesine başvurduk. Bununla birlikte, başta şiir tercümeleri olmak üzere, Arapça tercümesini yapamadığımız ve İngilizcesi’nin de Arapçası’yla uyuşmuyor olduğunda karar kıldığımız beyitler ve diğer bazı cümleleri atladığımızı,  köşeli parantez arasındaki noktalarla belli ettik.
Ömrünün hemen her anını ilme adamış büyük âlim el-Bîrûnî’ye karşı duyduğumuz derin saygı ve hayranlıkla, ortaya koyduğumuz bu tercümenin her bir harfini kaleme alırken onun inanılmaz dehasına lâyık olmaya çalıştık.  el-Bîrûnî’nin el-Cevâhîr ve diğer eserlerinde sıkça ifade ettiği üzere, başarı Allah’tandır.

Dr. Emine Sonnur Özcan
Temmuz 2014, Ankara

Computerized evaluation of Vibroseis similarity test data is the logical consequence of the increasing quality requirements for signal reproducibility and for synchronization of vibrators. The differences in start time and phase as well as an indication of local phasing problems between any two Vibroseis signals can be obtained from an analysis of the difference of their respective phase spectra. This method appears to be accurate and stable with respect to harmonics which usually plague the signals from transducers monitoring the motion of the vibrators'base plates.

Pearlproduction in Scandinavia from the late iron age until the mid 16th century lacks historical sources and few attempts have been made to describe the potential improtance small scale pearlfishing might have had during the medieval times for Scandianvian farmers and people who did not own land as a seasonal means for income. From the 1530s the Crown shows more interrest in the business and pearl fishing becomes an interrest for the whole nation.

The need for gemological knowledge has been recognized since the dawn of our industry. As is the case today, old-time dealers required technical information in order to make informed business decisions when purchasing goods. Understanding imitations was the main concern and, over time, the concerns evolved to more sophisticated mat- ters such as synthetics and then treatment disclosure, origin, and traceability. Gemological knowledge is now more com- plex and scientific, although classic gemology still remains accessible for the non-scientist.

Das kelten römer museum manching präsentierte vom 24. Juli 2021 bis zum 6. Februar 2022 die erweiterte Sonderausstellung »Kunst in Miniatur – Antike Gemmen aus Bayern«. Ihr Kernbestand umfasste Exemplare aus der Archäologischen Staatsammlung München, für die jeweils ihr bayerischer Fundort und meist sogar ihr archäologischer Kontext belegt sind. Dies ist insofern höchst bemerkenswert, als viele andere Gemmen bekanntlich ohne konkrete Provenienzangaben in öffentliche und private Sammlungen gelangen. Exklusiv für den Standort Manching wurde die Ausstellung noch bedeutend erweitert, insbesondere um eine gänzlich neue Abteilung zum reichen Nachleben der antiken Steinschneidekunst im mittelalterlichen und neuzeitlichen Bayern.

Turquoise in the Life of American Indians.
The mankind has known turquoise for more than ten thousand years. This is the only “live” mineral which can change its color with weather changes and the condition of its owner. Probably it is one of the reasons why it has always been surrounded by so many legends and superstitions in most cultures of the world. Turquoise was already mentioned in the first works about minerals and in a number of myths, especially those of the Navajo Indians of the U.S. South-West. In all continents it has been considered the happiest semi-precious stone which has taken a unique place in the history of civilizations and is still used in a great number of spheres of human activity.
The paper describes its major mineral qualities, deposits, the origins of its name, the most important and the oldest turquoise objects found during archeological digs, the use of turquoise in different countries and times, the legends about it, its role in different mythologies, traditional jewelry techniques of several North American Indian tribes, the varieties of the mineral and its imitations. A special emphasis is laid on the use of turquoise and the beliefs associated with it in American Indian cultures.
A Navajo myth about the goddess called Changing Woman (or Turquoise Woman) is studied separately as an explanation of a special attitude of American Indians to that stone and its very important role in their life up to the present day.

This review of the evolution of diamond cuts during the 16th to 18th centuries is illustrated with Portuguese jewellery and sacred objects from this period. We follow the evolution from point cuts already in existence prior to Portuguese navigational discoveries in the late 15th century, to table and rose cuts that co-existed for most of the 16th and 17th centuries, to the now-called old brilliant (or old mine) cut, which became popular a few decades after the discovery of the Brazilian diamond fields in the 1720s. The use of each cut and shifts in their popularity are discussed. These observations of diamond cuts in Portuguese jewellery and devotional objects may also be applicable to trends within wider European manufacture.

Sustainability concerns pushed by climate change have put the issue of coral on the agenda of major trade organizations such as CIBJO (the World Jewellery Confederation) where a Coral Commission has been working since 2016 to address these issues. Much of the information in this article comes from that important work.

History of Lapidaries / Gem Cutters. Histoire des Lapidaires, tailleurs-polisseurs de gemmes.
Résumé 1ère partie :
Orfèvres Joailliers, Lapidaires et Diamantaires ont été opposés dans de profondes rivalités afin d’établir en France les mérites artisanaux de leurs métiers. Il faut suivre une histoire millénaire pour appréhender la mise en place de leurs textes régisseurs et comprendre comment au fil de l’avancement des techniques, de leurs connaissances empiriques, du développement de leur art et malgré les contre-coups politiques et économiques, ces hommes ont érigé leurs statuts. Après avoir réuni les métiers de transformation des gemmes, les Lapidaires vont perpétuellement lutter contre les Marchands Orfèvres Joailliers pour la défense de leurs intérêts. Contrôlant les forains, submergés par les importations plus ou moins illégales de diamants brésiliens, anéantis par les puissants négociants flamands, surpassés par les cliveurs hollandais, défiés par les «banquiers» trafiquants, les Lapidaires s’affaibliront peu à peu jusqu’à perdre leur excellence naturelle qu’était la taille du diamant.

Résumé 2nd partie :
La première partie de cet article nous a conduit jusqu’au règne de Louis XV qui vit les Marchands Orfèvres Jouailliers l’emporter sur la corporation des Lapidaires, dès lors qu’ils furent les seuls autorisés à réaliser toutes montures des pierres acquises. Les Lapidaires se retrouvèrent, une nouvelle fois, contraints par des textes bridant leurs activités. Voyons ce que réserve la fin de l’histoire.


Abstract 1st part:
The gem-cutters / Lapidaries corporation finds its roots in the Middle Age, a period where we can trace their first records. They established themselves as a proper corporate entity at the end of the XVIth. Until the French Revolution (1789) they fought to get the title of Merchant, a title reserved to five corporations which included the Goldsmiths. From then on, they focused on the control of merchandise imported more or less legally by “bankers”, stallholders or Marranos diamond dealers belonging to powerful Flanders hub and from hegemonic Holland. After numerous trials, edicts, laws, blow-down, two centuries later Parisian Lapidaries had even lost their reputation as gem cutters.

Abstract 2nd part :
The first part of this article has taken us to the reign of Louis XV, who saw the Merchant Goldsmiths ‘Jouailliers’ taking precedence over the corporation of Lapidaries, since they were the only ones authorized to make all settings of the stones acquired. The Lapidaries found themselves, once again, constrained by texts restricting their activities. Let's see what the end of the story holds.

Picture 1: Rough and Cut and polished tanzanite Tanzanite was formed over 600 million years ago when Mt. Kilimanjaro erupted caused a unique set of conditions to form deep within the earth-heat and pressure mixed with rare chemicals such as Vanadium to allow this exceptionally rare gem stone to form. These conditions remained constant for the entire 600 million years and Tanzanite grew. It was first discovered by man in 1967 when an enormous grassfire swept the land below Kilimanjaro Mountain. As Tanzanite is a brownish color in its rough state, the crystals lying on the surface were never noticed until when the grassfire had burnt the land and heated the stones. They turned bright, glittering violet-blue in the sunlight and attracted the attention of some Maasai tribesmen. Tanzanite was named by Tiffany & Company (New York) and for the first ten years after its discovery Tiffany's had the exclusive right to this lovely gem stone. Today, after the liberalization of the Tanzanian economy, it is a free market. To date the only known reserve of Tanzanite gemstone in the world is a strip of 8km by 1km at Merelani area in Manyara region, Northern of Tanzania on the slopes of the legendary Mt. Kilimanjaro at Merelani Tanzania. To remember this you can recite Tanzanite Poem by Eng.Gilay Shamika; Tanzanite the uniqueness of Tanzania, Only Tanzanite in Tanzania, Only tanzanite with tantalizing tricolor, The stones on the foot of Mt.Kilimanjaro, The stones of 21st Century and The stones of December birthday. Geology Tanzanite is a thousand times rarer than diamonds and is trichroic, which means that in its rough form, it radiates three different colors from each of its crystallographic axes: blue, violet and TMAA

The article is devoted to the 37th book of the «Natural History» of
Pliny the Elder, On Gems. Various approaches to the interpretation and
translation of Pliny’s names of gems and concepts associated with them are considered with references to works in geology and gemology, as well as to the first experience of academic translation of the last five books of «Natural History» (33–37) by academician V. M. Severgin (1819). Pliny's distribution of gems in groups is analyzed, a hypothesis is proposed about the meaning of the Latin adjective candidus in the gemmae candidae group of colored gems, as referring not to their color, but to some special optical properties known in modern gemology (asterism, irisation, opalescence, etc.). The influence of the 37th book of «Natural History» on the practices of collecting gems, including those preserved in modern mineralogical museums, is considered.

Novgorodova D. D. «In Pliny... chrysoprasus is not chrysoprase, nor is topazus topaz or sapphirus sapphire». In INDO-EUROPEAN LINGUISTICS AND CLASSICAL PHILOLOGY – XXIII ((Joseph M. Tronsky memorial Conference). Proceedings of the International Conference, St. Petersburg, 24–26 June, 2019 / edited by Nikolai N. Kazansky. Part II (pp. 635–1208). St. Petersburg: Nauka, 2019 . P. 796-822.

Новгородова Д.Д. «У Плиния и хризопраз не хризопраз, и топаз не топаз, и сапфир не сапфир» // Индоевропейское языкознание и классическая филология – XXIII (чтения памяти И.М. Тронского). Материалы Международной конференции, проходившей 24-26 июня 2019 г. / Отв. редактор Н.Н. Казанский. Второй полутом (сс. 635-1208). СПб.: Наука, 2019. С. 796-822.

The Ukrainian jaspilites, occurring within Proterozoic
sediments of the Krivoy Rog Basin, are an important raw material
used in the national metallurgical industry. Some exhibit signifi cant
diversity of texture and colour and are suitable as decorative
rocks. In a few, the refl ective optical effects described as ‘tiger’seye’
and ‘falcon’s-eye’ are present. Quartz and iron-ore minerals
(hematite, magnetite, goethite) are the main rock-forming minerals
of the jaspilites, and carbonates (siderite, ankerite), amphiboles
(cummingtonite, grünerite), feldspars and apatite are subordinate
phases. In Ukraine, the decorative types of jaspilite are valuable for
making fancy goods such as vases and clocks, artistic jewellery, and
for the production of facing stone used especially for indoor design.

Preface; History of the Collection; Abbreviations; General Introduction; The uses of Gems; The choice of designs on gems; The technique of gem engraving; The materials used for ancient gems; Appreciation and collecting of gems; Gem engravers and their signatures; Forgeries; Catalogue; I. Greek; II. Etruscan and Italic; III. Roman intaglios, first century b.c. to fourth cantury a.d.; IV. Hellenistic and Roman Cameos and Works in the round, second century b.c. to fourth century a.d.; Concordance of the numbers in the 1920 and the 1956 editions of the catalogue; General index; Index of inscriptions.

Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals. Figure Pictures of a pyrope-almandine garnet and of a needle-shaped inclusion. The Raman spectrum of the inclusion is characteristic of rutile

Egypt’s Red Sea island of Zabargad, also called St. John’s Island, is arguably the world’s most famous source of gem olivine, or peridot.  Both the island and its eponymous gemstone were called “topazos” by ancient writers.  Although much has been written about Zabargad’s unusual geology and modern mine workings, an ancient peridot mine had not been verified until a geo-archaeological expedition to the island in 2010 confirmed the existence of ancient mine workings and associated ruins of buildings and a water well.  In the first of two companion articles, the findings from this expedition are discussed in relation to literary references on the subject and the relationship between Zabargad and Berenike, the Ptolemaic-Roman port city on the Egyptian mainland opposite the island and a major emporium for the maritime trade with eastern Africa, the Persian Gulf and India.  Peridot was imported via this port-of-entry into the Graeco-Roman world, where it was used primarily for ring stones.  In the second article, the historiography of ancient literary sources on both the identity and geographic origins of the gem known today as peridot is examined with reference to the 2010 expedition to Zabargard and a survey of extant ancient engraved gems carved from peridot. Among other possible sources of peridot in antiquity is a second Red Sea island called “Cytis” by the Roman encyclopedist Pliny the Elder (d. AD 79). The association of Cytis with modern Kod Ali Island,  located a few kilometers off the coast of Eritrea, is also discussed.

First of an ongoing series from Danna G. Hallmark taken from a forum thread on ISG Website:
1. "If You Don't Know History, You Don't Know Squat" introduces the reader to the inefficiencies of pearl evaluation and classification today.
2. "So. Who Cares Anyway? What Does It Matter?" is a short addition of a comment from a reader.

Many spiritual teachers have told us of a spiritual power which resides in precious stones. 

According to Saint Thomas Aquinas (1225-1274),
. . . there is no doubt that gemstones have something of the hidden power of the bodies that are above the vault of heaven . . . they have something in them that is beyond the powers of the four basic elements of nature . . . it appears evident that some stones have something of the fifth essence . . . some stones have something in them of the nature of the stars. [G. Ronald Murphy, S.J., Gemstone of Paradise, pp. 66-67.]

According to Hildegard of Bingen, stones possess the qualities of the ancient elements of fire and water:
All stones have fire and wetness within them.  But the devil finds precious stones abhorrent, he hates and despises them because they are a reminder – their beauty shone forth before he corrupted the glory given to him by God.  He also hates them because precious stones are born of fire, the thing in which he has his punishment.[ Hildegard of Bingen, “De Lapidibus,” in Patrologia Latina, ed. Jacques-Paul Migne (Paris: Migne, 1844), vol. 197, col. 1247, quoted in Murphy, Gemstone of Paradise, p. 55.]

Hildegard further theorizes that gems are created when seawater contacts hot volcanic rock and forms a foam, which adheres to rock, hardens and dries into a gemstone within a few days in the heat of the sun.  These gems are then carried by rivers to all the parts of the earth.  Because the gems are formed from fire and water, they possess great inner, radiatory energy.  Those who know the secrets of releasing their great condensed energy, according to Hildegard, will be able to use their powers for healing.[ G. Ronald Murphy, S.J., Gemstone of Paradise, pp. 55-56.]

The Tibetan Master tells us that:

The mineral kingdom is responsive to that type of energy which is the lowest aspect of fire, of those internal furnaces which exert an influence upon the elements in the mineral world, and which resolve these atomic lives into a gradual series of ever-higher types of mineral energy.

By Celeste Jamerson

The origins and identities of the gem minerals known in antiquity have been construed primarily from ancient literary sources.  Some of the most important texts are not preserved in the translation of original manuscripts but are versions produced later, often several centuries later. They may survive only as fragmentary works or paraphrased in the works of other writers. Sometimes they survive in successive editions which bear accumulated errors and defects iterated over centuries. Some of the most significant works and problems of their handling in translation have been discussed. Attention has been devoted especially to lexical problems associated with trying to reconcile ancient and modern mineral taxonomies, inconsistent usage of gem terms, some of which are deprecated, and contemporary bias of translators.
Examination of approximately 1,100 objects representing the range of lapidary materials known to ancient gem cutters provided objective reference to consider some of the most troublesome gemstone identities and presumed gemstone origins that have come to be generally accepted as true. Empirical observations of the gems examined, archaeology, and the discovery of new gem sources in recent decades suggest that updated translations of some important treatises are needed, especially Books 36-37 of Pliny the Elder’s »Natural History«, which was published more than 50 years ago.
Most of the gems examined came from private or museum collections whose provenience dates between the 17th and 20th centuries. Lacking known archaeological context in most instances hinders tracing the mechanism of transmission or the path traveled between a raw lapidary material’s origin and its eventual deposition as a fashioned object in its date- and place-specific cultural setting.

Shoreline and shelf-edge trajectories describe the migration through time of sedimentary systems, using geomorphological breaks-in-slope that are associated with key changes in depositional processes and products. Analysis of these trajectories provides a simple descriptive tool that complements and extends conventional sequence stratigraphic methods and models. Trajectory analysis offers four advantages over a sequence stratigraphic interpretation based on systems tracts: (1) each genetically related advance or retreat of a shoreline or shelf edge is viewed in the context of a continuously evolving depositional system, rather than as several discrete systems tracts; (2) subtle changes in depositional response (e.g. within systems tracts) can be identified and honoured; (3) trajectory analysis does not anticipate the succession of depositional events implied by systems-tract models; and (4) the descriptive emphasis of trajectory analysis does not involve any a priori assumptions about the type or nature of the mechanisms that drive sequence development. These four points allow the level of detail in a trajectory-based interpretation to be directly tailored to the available data, such that the interpretation may be qualitative or quantitative in two or three dimensions. Four classes of shoreline trajectory are recognized: ascending regressive, descending regressive, transgressive and stationary (i.e. nonmigratory). Ascending regressive and high-angle (accretionary) transgressive trajectories are associated with expanded facies belt thicknesses, the absence of laterally extensive erosional surfaces, and relatively high preservation of the shoreline depositional system. In contrast, descending regressive and low-angle (nonaccretionary) transgressive trajectories are associated with foreshortened and/or missing facies belts, the presence of laterally extensive erosional surfaces, and relatively low preservation of the shoreline depositional system. Stationary trajectories record shorelines positioned at a steeply sloping shelf edge, with accompanying bypass of sediment to the basin floor. Shelf-edge trajectories represent larger spatial and temporal scales than shoreline trajectories, and they can be subdivided into ascending, descending and stationary (i.e. nonmigratory) classes. Ascending trajectories are associated with a relatively large number and thickness of shoreline tongues (parasequences), the absence of laterally extensive erosional surfaces on the shelf, and relatively low sediment supply to the basin floor. Descending trajectories are associated with a few, thin shoreline tongues, the presence of laterally extensive erosional surfaces on the shelf, and high sediment supply to basin-floor fan systems. Stationary trajectories record near-total bypass of sediment across the shelf and mass transfer to the basin floor.