Its total land area is -- slightly larger than Washington, D. C. -- consisting of five rugged, volcanic islands and two coral atolls.

Amethyst is produced in abundance from the state of Minas Gerais in Brazil where it occurs in large geodes within volcanic rocks.

The first deposit on the wall of a cavity, forming the " skin " of the agate, is generally a dark greenish mineral substance, like celadonite, delessite or " green earth ", which are rich in iron probably derived from the decomposition of the augite in the enclosing volcanic rock.

Geologists believed prior to the mission that both of these formations were volcanic in origin ; however, samples returned from the lunar surface have since proven this hypothesis is incorrect.

The southern volcanic part of the island is rugged and mountainous, and largely barren.

Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcanic eruptions.

It has volcanic islands and is steep and hilly.

sometimes referred to as ' the hinge of Africa ;' throughout the country there are areas of thermal springs and indications of current or prior volcanic activity ; Mount Cameroon, the highest mountain in Sub-Saharan west Africa, is an active volcano

A small volcanic outcrop rising to on its southeast side is referred to as " Clipperton Rock ".

Land elevations average, though Clipperton Rock, a barren volcanic outcrop located in the atoll's southeast, is considerably higher and forms the island's tallest point.

The highest point is Cerro Chirripó, a volcanic mountain with an elevation of ( part of Chirripó National Park ).

The most recently formed of the four islands in the archipelago, it is also of volcanic origin.

Because of greater weathering of the volcanic rock, the soil is relatively rich in some areas.

Note: it is reported in the scientific literature that some " shock " features, such as small shatter cones, which are often reported as being associated only with impact events, have been found in terrestrial volcanic ejecta.

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption.

A collapse is triggered by the emptying of the magma chamber beneath the volcano, usually as the result of a large volcanic eruption.

If enough magma is ejected, the emptied chamber is unable to support the weight of the volcanic edifice above it.

If volcanic activity continues, the centre of the caldera may be uplifted in the form of a resurgent dome such as is seen at Cerro Galán, Lake Toba, Yellowstone, and so on, by subsequent intrusion of magma.

None of these worlds have plate tectonics, which contributes approximately 60 % of the Earth's volcanic activity ( the other 40 % is attributed to hot spot volcanism ).

The volcanic activity of Mars is concentrated in two major provinces, Tharsis and Elysium.

Geologically, Dominica is part of the rugged Lesser Antilles volcanic arc.

The valley of desolation is a sulfurous valley of volcanic vents and hot springs that inhibits significant plant growth-in stark contrast to the surrounding rain forest.

Dominica's rugged surface is marked by its volcanic past.

since Bourbon whiskey, though of Kentucky origin, is at least as much favored by liberals in the North as by conservatives in the South.

This is the only case in modern history of a people of Britannic origin submitting without continued struggle to what they view as foreign domination.

However, it is important to trace the philosophy of the French Revolution to its sources to understand the common democratic origin of individualism and socialism and the influence of the latter on the former.

It is difficult to pinpoint the time of origin of the state purchasing automobiles for use of employees in Rhode Island.

There is an oral tradition among the members of the population in regard to the origin and subsequent separate status of the group in the larger society.

Apparently their origin is humble, their approach to life direct and unsophisticated.

If the cutting force, Af, is plotted against film thickness, a straight line should result passing through the origin and having slope Af.

Because the food is selected with thought for its nutritional value, care for its origin, and prepared in a manner that retains the most nutrients, the food does taste good.

The material is all basically of folk origin, gleaned from every section of Poland.

The inspiration oracular cult was probably introduced into Greece from Anatolia, which is the origin of Sibyl, and where existed some of the oldest oracular shrines.

Because all clades are represented in the southern hemisphere but many not in the northern hemisphere, it is natural to conjecture that there is a common southern origin to them.

Wormwood, a genus that includes the sagebrush, is used as a source of flavoring for absinthe, a bitter classical liquor of European origin.

The debate is over the origin of their similarities.

Allegiance is formed from " liege ," from Old French liege, " liege, free ", of Germanic origin.

Angst means fear or anxiety ( anguish is its Latinate equivalent, and anxious, anxiety are of similar origin ).

German Alpen is the accusative in origin, but was made the nominative in Modern German, whence also Alm.

This religious explanation is supported by modern Pueblo beliefs about a North Road leading to their place of origin and along which the spirits of the dead travel.

The precise nature of the origin of this urn is matter of dispute.

As neither tune is attributed and both show elements of oral transmission, scholars can only speculate that they are possibly of British origin.

Virtually nothing is known of his parents, family background, or origin.

It is clear that widespread respect was paid to animals as the abode of dead ancestors, and much of the cults to dangerous animals is traceable to this principle ; though there is no need to attribute an animistic origin to it.

In certain obscure magical writings of Egyptian origin ἀβραξάς or ἀβρασάξ is found associated with other names which frequently accompany it on gems ; it is also found on the Greek metal tesseræ among other mystic words.