Dr David Penney and Dr David Green (UK) It is almost two decades since the original blockbuster movie, Jurassic Park, brought the existence of fossil insects in amber (fossilised tree resin) into the limelight. Since then, numerous books and research papers have been published. Fossiliferous amber deposits are still being discovered, including, in recent years, the first major deposits in Africa, India and Australia. The market for fossils in amber experienced a boom in the 1990s, but it has since declined for various reasons, including fakery, copal (sub-fossil resin) being sold as genuine amber and the current economic conditions. Nevertheless, there are many reputable sources for those wishing to develop their passion for amber – a substance that has fascinated people for millennia. It has been endowed with mystical, magical and medicinal properties, and used as an artistic medium and in jewellery. However, today, it is probably most famous for the fossil insect inclusions it preserves with life-like fidelity. It is these that are the focus of this article. This is the second part of a series of articles on fossils in amber. The first is: Fossils in amber (Part 1): Preparation and study. Important fossiliferous deposits There are almost 200 known amber deposits around the world, some dating from as early as the mid-Carboniferous. Relatively few have produced abundant biological inclusions and those that do occur only in strata of Tertiary or Cretaceous age. Many of these ambers were produced by different tree families under somewhat different environmental conditions. … Read More
Steven Marquez (USA) The specimen displayed is a variety of microcline feldspar, referred to as amazonite. Many jewellers love this mineral for making cabochons because of its brilliant colour, which is thought to be caused by traces of lead and water. The gemstone is called the “Stone of Hope”, because it is thought to inspire confidence and hope. The name “amazonite” comes from the Amazon River in South America. It can also be found at the Lake George area, along with smoky quartz. However, its occurrence is very limited. Fig. 1. This specimen of amazonite was mined in the Lake George area of Colorado. ASW Veatch specimen (photo Steven Marquez). Facts on fileChemical formula: KAlSi3O8Composition: potassium aluminium silicateColour: bluish green or verdigris greenCrystals: triclinicCleavage: good, two directions at 90oFracture: unevenLustre: vitreousStreak: whiteHardness: 6Transparency: noneSpecific gravity: 2.56-2.57An amazonite haiku: Microcline feldspar. Bluish or verdigris green. The perfect jewellery Further reading Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals. New York: Alfred A. Knopf, 1990. Hall, Cathy. Smithsonian Handbooks: Gemstones. New York . Dorling-Kindersley, 2002. About the author Fig. 2. Author, Steven Marquez, is active inthe study of rocks and minerals in the Pikes Peak region. (Photo by Steven Veatch.) Steven Marquez is an Earth Science Scholar with the Pikes Peak Pebble Pups and is a member of the Colorado Springs Mineralogical Society. He is a frequent contributor to magazines and newspapers, and is in the 8th grade. He lives in Colorado Springs.
Trevor Devon (UK) At some time, I suppose we have all collected rocks or minerals when we were travelling to new places, mostly as mementos, but nothing quite beats the buzz of collecting specific minerals from classic locations with like-minded colleagues. This type of collecting implies you know something of the geology and mineralogy of the location, what sort of rock to explore (often with a sledgehammer to start with) and what colour and shape the minerals are likely to be found in. Of course, it helps to travel with colleagues who have been there before and can show you what to look for. That is one of the reasons why I joined the Sussex Mineralogy and Lapidary Society (SMLS) a few years ago. Fig. 1. Behind the scenes at the mineralogy department of the Royal Ontario Museum, Toronto. Since 1980, SMLS has conducted trips to many parts of the world, including the USA and Canada, India, Namibia in Africa, and several countries in Europe. Such trips usually attract around a dozen or so participants and are often organised with a bit of tourism so that non-mineralogical spouses can join in. I have been fortunate enough to join recent SMLS trips to Cornwall, Isle of Skye, India, the South of France, the USA, Canada, the Caldbeck Fells in Cumbria, and Bulgaria. Perhaps I should start with the basic question of why I collect minerals. First of all, I think some of us are born collectors – for example, I collect … Read More
Dr Robert Sturm (Austria) Compared to the geological architecture of other European countries not exceeding a total area of 100,000km², the geology of Scotland is characterised by an unusual diversity of geological features. Due to its tectono-metamorphic complexity Scotland attracted numerous earth scientists in the eighteenth and nineteenth centuries, whose main aim was the development of theories about, on the one hand, rock formation and, on the other, metamorphic alteration of initial lithologies. Besides being the preferred target of foreign scientists, the country has also produced its own important figures in the history of geological research. In this context, James Hutton – the “father of modern geology”, after whom, for example, ‘Hutton’s Unconformity’ at Siccar Point in Berwickshire is named – has to be mentioned, but also Hugh Miller and Archibald Geikie provided valuable contributions to the enlightenment of various geological problems. Fig. 1. Geological subdivision of Scotland into four main units. Returning to the geology of Scotland, it is possible to subdivide the country into four main geological and geographical units. The Southern Uplands, which extend south of the Southern Uplands Fault, are mainly composed of sedimentary rocks dating back to the Silurian and the Devonian. The Central Lowlands or Midland Valley, which border the Southern Uplands Fault on the north, represent a rift zone that chiefly comprises Palaeozoic rocks of both sedimentary and volcanic origin. North and west of the Highland Boundary Fault lies the Highlands and Islands, which, due to their geological diversity, can be further subdivided … Read More
Steven Marquez (USA) Amethyst is the violet to purple variety of quartz. It is often associated with albite and orthoclase in pegmatites. Fine specimens of amethyst can be classified as semiprecious gemstones. This specimen was found in Cripple Creek Colorado, as a near surface deposit on the David Leighton gold mine, owned by Steven Wade Veatch across from the hardware and grocery store on Teller County 1. The short, stubby amethyst crystals formed gas pockets in a hot, welded ash deposit that once covered the landscape of Cripple Creek. Amethyst is also mined in great quantities from the state of Minas Gerais in Brazil. A deep purple amethyst is commonly found in Uruguay. The colour purple is a royal colour, which is why amethyst is often used in jewellery for kings and queens. It was highly valued by Egyptians and the ancient Greeks believed that it protected against intoxication. Amethyst is the birthstone for February. Fig. 2. Note the faint crosswise striations on the surface of the amethyst crystal. This is one of the diagnostic features of quartz. The specimen is from the Steven Veatch collection. Photo by Steven Marquez. Facts on fileChemical formula: SiO2Composition: silicon dioxide; the colour is caused by iron or manganese impuritiesColour: purple, greasy lustreStreak: whiteHardness: 7Crystal system: hexagonalTransparency: transparent to translucentSpecific gravity: 2.65Lustre: vitreousCleavage: noneFracture: conchoidalTenacity: brittleGroup: silicates, tectosilicatesHaiku Brilliant purple Never ceasing to amaze Glowing like the stars About the author Fig. 2. Steven Marquez, seen working on the curation and cataloguing of the … Read More
I have been fortunate enough to review for this magazine a large number of books from the Dunedin series of guides introducing aspects of the different sciences, especially the earth sciences. And Introducing Mineralogy continues the high standard set by its predecessors. It is slightly larger than some of the other guides in the series, but is still beautifully illustrated, nicely written and very informative.
These three guides by Robert Westwood are in the same simple format. All are local geological guides to specific areas of the UK and all are illustrated by lovely full colour photographs. They all contain simple, introductory geological introductions for the uninitiated, and then more detailed expositions of what makes the regions so special.
This is the fourth book in a series published by Dunedin that I have been lucky enough to review – the others being on palaeontology, geology and volcanology. And this is as good as the others. However, it is not an easy book to read.
Normally, I wouldn’t be interested in semi-precious stones and other pretty things. Personally, I prefer grubbing around in the dirt, perhaps for those far more beautiful, elusive and perfectly formed Cretaceous terebratulids or Silurian trilobites. However, some semi-precious stones have the advantage of also providing a tangible link to the ancient history of life.
Nowadays, people don’t do geology – they do ‘earth sciences’ – and this book is very much in that mould. That’s not to say this is a problem.
Deposits magazine has covered the science and appeal of agate in some detail over the last few years. Indeed, this issue has another in Wayne Sukow’s excellent series on the science of Lake Superior agate formation.
Here at Deposits, we like our amber and this certainly isn’t the first book on the subject I have reviewed. In fact, over the years, we have published many articles on the fossilised sap and its inclusions, and have just finished publishing a short, two-article series by the authors of this excellent little publication.
Over a period of 20 years, Ian Tyler has written a series of books on the metalliferous mining industry of the English Lake District and this has clearly been a significant labour of love for him.
Terry Moxon likes his agates. It is easy to see his enthusiasm and it is just as easy to appreciate it from this short book on the science of these colourful minerals. However, his is not just a casual interest.
For many years, the Geologists’ Association has published some of the best geological guides to the UK (and a few other places). This new one, the 67th in the series, covers the Dalradian of Scotland.
The island of Cyprus is a truly classic area of geology in Europe. Perhaps nowhere else on Earth does so small an area provide such an excellent illustration of the dynamics of Earth processes through abundant exposures of spectacular and diverse geology.
The Caithness area of Scotland is important for its geology, but is also well known for its palaeontology. The area even once had its own ‘gold rush’ and you can still try your luck at panning there today at Kildonan.
For a long time Watchet has been known to be a superb location for those interested in both fossils and geology but surprisingly, the location has had little in the way of media attention. However, within the last couple of years, this area has begun to attract a lot of interest and this book will further increase its growing popularity.
Minerals of Britain and Ireland is a comprehensive account of the minerals found in Britain, Ireland and the surrounding islands. At over 600 pages and illustrated throughout by over 550 images (mostly in colour), the book provides exhaustive coverage of the remarkably wide range of minerals found in this part of the world.
Dorling Kindersley (DK) are well-known for producing popular reference media for beginners and enthusiasts. No doubt, most readers will be familiar with their ‘Eyewitness Guides’. The Eyewitness Handbook of fossils, certainly makes a useful starting point for anyone new to geology or palaeontology.