Schist is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates. This texture reflects a high content of platy minerals, such as micas, talc, chlorite, or graphite. These are often interleaved with more granular minerals, such as feldspar or quartz.
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous. Tuff composed of sandy volcanic material can be referred to as volcanic sandstone.
Rhyolite is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent to granite.
Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III) inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The specific gravity of jasper is typically 2.5 to 2.9. Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.
The Alban Hills are the caldera remains of a quiescent volcanic complex in Italy, located 20 km (12 mi) southeast of Rome and about 24 km (15 mi) north of Anzio. The 950 m (3,120 ft) high Monte Cavo forms a highly visible peak the centre of the caldera, but the highest point is Maschio delle Faete approximately 2 km (1.2 mi) to the east of Cavo and 6 m (20 ft) taller. There are subsidiary calderas along the rim of the Alban Hills that contain the lakes Albano and Nemi. The hills are composed of peperino, a variety of tuff that is useful for construction and provides a mineral-rich substrate for nearby vineyards.
Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, and cinder cones.
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869–1950) coined the term ignimbrite from the Latin igni- [fire] and imbri- [rain].
The Forum Holitorium is an archaeological area of Rome, Italy, on the slopes of the Capitoline Hill. It was "oddly located" outside the Porta Carmentalis in the Campus Martius, crowded between the Forum Boarium and buildings located in the Circus Flaminius.
A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption. A maar characteristically fills with water to form a relatively shallow crater lake, which may also be called a maar.
Mark Howard James professionally known as The 45 King, is an American hip hop producer and DJ from The Bronx, New York. He began DJing in the mid-1980s. His pseudonym, the 45 King, came from his ability to make beats using obscure 45 RPM records.
Trajan's Forum was the last of the Imperial fora to be constructed in ancient Rome. The architect Apollodorus of Damascus oversaw its construction.
Tuff Gong is the brand name associated with a number of businesses started by Bob Marley and the Marley family. 'Tuff Gong' comes from Marley's nickname, which was in turn an echo of that given to founder of the Rastafari movement, Leonard "The Gong" Howell.
Opus reticulatum is a facing used for concrete walls in Roman architecture from about the first century BCE to the early first century CE. They were built using small pyramid shaped tuff, a volcanic stone embedded into a concrete core. Reticulate work was also combined with a multitude of other building materials to provide polychrome colouring and other facings to form new techniques. Opus reticulatum was generally used in central and southern Italy with the exception being its rare appearance in Africa and Jericho. This was because of tuff’s wider availability and ease of local transport in central Italy and Campania compared to other regions.
Piperno is a magmatic rock present in areas where there has been volcanic activity. Piperno abounds in Campania; the areas from which it was obtained were the city of Quarto, Soccavo, Pianura and Nocera Inferiore in the supervolcano region of the Phlegraean Fields. The Piperno layer, with the overlying Breccia Museo, is clearly visible at the base of the Camaldoli hill, in the Soccavo and Verdolino areas.
Fort Rock is a tuff ring located on an ice age lake bed in north Lake County, Oregon, United States. The ring is about 4,460 feet (1,360 m) in diameter and stands about 200 feet (60 m) high above the surrounding plain. Its name is derived from the tall, straight sides that resemble the palisades of a fort. The region of Fort Rock–Christmas Lake Valley basin contains about 40 such tuff rings and maars and is located in the Brothers Fault Zone of central Oregon's Great Basin. William Sullivan, an early settler in the area, named Fort Rock in 1873 while searching for lost cattle.
The Temple of Vespasian and Titus is located in Rome at the western end of the Roman Forum between the Temple of Concordia and the Temple of Saturn. It is dedicated to the deified Vespasian and his son, the deified Titus. It was begun by Titus in 79 after Vespasian's death and Titus's succession. Titus’ brother, Domitian, completed and dedicated the temple to Titus and Vespasian in approximately 87.
The Pons Cestius is an ancient Roman bridge connecting the right bank of the Tiber with the west of the Tiber Island in Rome, Italy. In Late Antiquity, the bridge was replaced and renamed the Pons Gratiani. It is also known as Ponte San Bartolomeo. No more than one third of the present stone bridge is of ancient material, as it was entirely rebuilt and extended in the 19th century, after numerous earlier restorations.
The Temple of Janus at the Forum Holitorium is the second known temple dedicated to Janus, besides the temple of the same name located in the Roman Forum.
It is known that it stood "close to the Theatre of Marcellus" and "outside Porta Carmentalis" and that feasts took place there in August and October.
Leucitite or leucite rock is an igneous rock containing leucite. It is scarce, many countries such as England being entirely without them. However, they are of wide distribution, occurring in every quarter of the globe. Taken collectively, they exhibit a considerable variety of types and are of great interest petrographically. For the presence of this mineral it is necessary that the silica percentage of the rock should be low, since leucite is incompatible with free quartz and reacts with it to form potassium feldspar. Because it weathers rapidly, leucite is most common in lavas of recent and Tertiary age, which have a fair amount of potassium, or at any rate have potassium equal to or greater than sodium; if sodium is abundant nepheline occurs rather than leucite.
Vulcan's Throne is a cinder cone volcano and a prominent landmark on the North Rim of the Grand Canyon in Arizona, United States. The volcano is adjacent the Colorado River, as it is the source material for Lava Falls and Lava Falls Rapids one of the largest rapids of the Colorado. Vulcan's Throne, about a mile (1.7 km) west of Toroweap overlook, is part of the Uinkaret volcanic field. The journals of traveler George Corning Fraser record a trip to the summit of Vulcan's Throne in 1914. At the time, the surrounding area was used for sheep grazing, and a small reservoir had been constructed at the base of the volcano. Fraser wrote that
Vulcan's Throne is a pure cinder cone covered with scoriae, cinders, clinkers and peperino lying loose on the surface, with a slope, as near as I could measure, from 28° to 31°. A little sage, many cacti and perhaps some other similar low plants grow on it, but otherwise nothing. Climbing it was like ascending a sand-dune. Every step forward involved slipping half way back and boots were soon filled with painful bits of stone.
