Day 12 : I found this little pyritised ammonite at the bottom of one of my rock drawers. With the marl matrix rapidly disintegrating unfortunately I don't think this fossil is long for this world so I thought I'd better photograph it now. It is from the Liassic of the UK somewhere, …
Day 11 : The dark mineral here is sphalerite or zincblende, the main or mineral of zinc. It is mostly zinc sulphide with some iron. The white mineral is calcite and with the sphalerite forms a vein infilling in Lower Carboniferous Limestone. This sample comes from the old mine spoil …
Day 10 : Again from the back garden collection, today’s rock is a conglomerate. I find conglomerates and breccias the most aesthetically pleasing of rocks. This one is from Monkstone Point, Pembrokeshire, Wales and is a conglomerate containing not only vein quartz, but clasts of siderite nodules (iron carbonate), reworked …
Day 9 : From the back garden collection – Blue John, the purple variety of fluorspar (calcium fluoride). The name is derived from the French 'bleu et jaune" which decribes the colours found. This sample was collected near Castleton on one of my first ever geology field courses, to the …
Day 8 : Chile Saltpeter (or Salitre) is a deposit of sodium nitrate found in the Atacama Desert region of Chile. It is used in the making of of fertilizers, explosives, solid rocket propellants and food preservatives. It was quarried extensively prior to World War 1 and its economic significance …
Day 7 : Today’s mineral deskcrop specimen comes from Cumbria, England close to the Florence Mine. The sample shows the botryoidal (resembling a bunch of grapes) habit of the iron mineral haematite with some minor calcite.
Day 6 : The second deskcrop from my collection is Larvikite, from the Norwegian town of Larvik. Larvikite is technically a monazite, an intermediate igneous intrusive rock composed of approximately equal amounts of plagioclase and orthoclase feldspars with minor amounts of hornblende and biotite. The feldspars form a perthite texture, …
Day 5 : The first of my deskcrops. This sample of otherwise unremarkable fine-grained grey rhyolite has an important minor component – there is gold in that there rock. The small light coloured specks are native gold. The rock is from El Guanaco Mine, Santa Catalina, Antofagasta Province, Antofagasta Region, Chile
Day 4: Visiting my mother on the way home from Morocco. Here is one of my old rock collection still sitting on the window sill of my old bedroom. This is the Anglesey Blueschist (560-550Ma) from near Llanfairpwllgwyngyll, Anglesey, North Wales. The type locality is at the base of the …
Day 3: All day travelling back from Morocco so little in the way of photographic opportunities for rocks. Here is a plagiogranite from the floor of Casablanca airport.