Quartz

One of the most abundant mineral in Earth's crust, and it is magmatic, sedimentary or metamorphic. Su clase es el óxido, su estructura es trigonal, su material es de cristal que se forma con una dureza de siete y un brillo característico. Its chemical formula is SiO2 .

Properties:
-Piezoelectric properties: it is a phenomenon presented by certain crystals when subjected to mechanical stresses acquire an electric polarization in mass, appearing a potential differenceand electric charges on its surface.
-Resonant behavior: the strengthening of certain sound frequencies as a result of the coincidence of similar waves
-Thermoluminescence: the ability to emit light when heated.

Varieties of quartz
The quartz, pure and free of impurities is called rock crystal.
When the tone changes to brown or gray smoky quartz is called, if purple amethyst, citrine ifyellow.

amocky quarz

pinck quarz

Andrea Mendaña Delso

The giant armadillo.

This strange animal, called "Tatu carreta" too, habits in South America on the east of the Andes and in Argentina, in the forests zones.
It's 150-160 cm long, where 50 cm is only the tail. Their carapace is a defense against predators but they can move it and protect itself like a ball. Their nails are of 20cm, and the haven´t got hair.
It is an almost solitary mammal, accompanied only when it gets a couple. They live about 12 to 15 years. They reach sexual maturity between 9 to 12 months. Procreation one to two babies take about four months. They live in very large dispersal areas.

The Armadillos are one of the oldest families of mammals in South America and are represented by numerous species. The giant armadillo is represented as a prehistoric animal, descended from a family lineage of the continent with giant ancestors such as battleships and giant sloths glyptodonts. Unfortunately, man is getting them extinct. Their diet is supplemented with carrion, snakes and plants. It traveled almost 3,000 meters everyday looking for their favorite food. It has 18 to 24 teeth per jaw, and tongue adapted for this purpose with special mandibular glands, the function of secreting a sticky substance that, by covering the surface of the tongue, easy to capture insects. They can weigth 60kg.
It is hunted for its meat. It captures him to take to zoos, museums, collectors, or to fill the shell as a sounding board.
Its greatest and almost only predator is man.

By: Alba González Otero.