Lazurite ( (Na,Ca)8 (Al,Si)12O24(S,SO)4 ), is one of a number of related feldspathoid minerals, which occur in silica-poor igneous rocks collectively termed the Sodalite Group. Also part of the group are nosean (or noselite) along with a clacium-bearing type named Haüyne.
Sample of Haüyne from Mayen, Eifel Mountains, Rhineland-Palatinate, Germany. Attribution: Rob Lavinsky, iRocks.com
Lazurite is a [...]
When starting out on preparation most hobbyist collectors will find the use of a rotary tool kit with interchangeable heads immensely versatile. Along with an electric engraver, steel probes and craft knives, these can be helpful for carefully picking away and removing the surrounding sediments. Fortunately the tools just mentioned do not take up much space and can be purchased at very little expense to the user.
The cliffs for about 2 km to the west of Cowbar Nab are capped by glacial till, bedrock being at 40 to 50m O.D. Staithes Beck has cut a deep channel through the till in to the solid strata. On the coast, several landslips and rockfalls can be seen and, in contrast, examples of slow, gradual marine erosion. The marine erosion has been the subject of detailed studies by Agar (1960) and by Durham University in recent years.
The alum works was started in the mid-17th century and closed in about 1860. There was a major redevelopment about 1800 when a new alum house was constructed by Hummersea beach. The history and industrial archaeology of the alum works has received much attention in recent years and, in particular, there is the major survey by English Heritage (Hunt et al. 2004). The main sites are included in the mini-geotrail.
Boulby Quarry and the sea cliffs beneath (making use of the tracks down to the shore) are where several 19th century and, more recently, geologists such as Chowns made measured sections. That by Lewis Hunton (1836) is the most notable as he independently recognized the importance of collecting fossils in-situ, and relating the fossils found to the beds in which they occur bolstering the emerging concept of biostratigraphy.
Welcome to the latest offering in the TVRIGS Rock of the Month series of articles. This month I thought that we might examine a broad group of deposits known as argillaceous rocks, collectively referred to as argillites (clay rocks), as opposed to arenites (sandstones) and rudites (conglomerates, tillites and breccias).
Derived from the Latin Argilla – [...]
These are an extinct order of arthropod (animals having a jointed and segmented body plan) which make their first appearance in the fossil record during the Cambrian Period, commencing about 520 million years ago. Trilobites, meaning ‘three-lobes’, are some of the earliest known arthropods and lived on the sea floor at a variety of [...]
A well exposed rock outcrop known as Chiastolite Slate, part of the Ordovician Skiddaw Group, can be seen in the Glenderaterra Valley which is located in the northern area of the Lake District. The exposure (grid ref. NY 299 269) is by an unnamed stream next to the path leading from the Blencathra Centre, NY [...]
Water, the Hub of Life.
Water is its mater and matrix, mother and medium.
Water is the most extraordinary substance!
Practically all its properties are anomalous, which enabled life
to use it as building material for its machinery.
Life is water [...]
For this month’s article we are going to take a look at a commonly occurring mineral having a long history of association with humankind. Fool’s Gold is a common name used to describe a number of different minerals including weathered biotite mica, though most frequently the name [...]