Vibrance

Murano glass is a famous product of the Venetian island of Murano. Located off the shore of Venice in Italy, Murano has been a commercial port as far back as the 7th century. By the 10th century, the city had become well-known for its glassmakers, who created unique Murano glass.

The process of making Murano glass is rather complex. Most Murano glass art is made using the lampworking technique. As the glass passes from a liquid to a solid state, there is an interval wherein the glass is soft before it hardens completely. This is when the material can be shaped.

The technique known as Millefiori begins with the layering of colored liquid glass, which is then stretched into long rods called canes. Two glassmakers each pull the glass as they walk in opposite directions. After cooling, the glass rod is sliced so that the pattern shows through each slice. Each slice of the millefiori Murano glass is called a murrine.

When cold, these canes are then sliced in cross-section, which reveals the layered pattern. Each layer of molten color is molded into a star, then cooled and layered again. When sliced, this type of murrine has the appearance of many flowers, thus mille (thousand) fiori (flowers).

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Protection

Amethyst is a violet variety of quartz often used in jewelry. In the 20th century, the color of amethyst was attributed to the presence of manganese. More recent work has shown a complex interplay of iron and aluminium is responsible for the color. On exposure to heat, amethyst generally becomes yellow, and much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely burnt amethyst. Veins of amethystine quartz are apt to lose their color on the exposed outcrop.

Amethyst was used as a gemstone by the ancient Egyptians and was largely employed for intaglios. The Greeks believed amethyst gems could prevent intoxication, while medieval European soldiers wore amethyst amulets as protection in battle. Beads of amethyst were found in Anglo-Saxon graves in England.

In Greek mythology, Dionysus, the god of intoxication, was pursuing a maiden named Amethystos, who refused his affections. Amethystos prayed to the gods to remain chaste, which the goddess Artemis granted and transformed her into a white stone. Humbled by Amethystos’s desire to remain chaste, Dionysus poured wine over the stone as an offering, dyeing the crystals purple.

Variations of the story include that Dionysus had been insulted by a mortal and swore to slay the next mortal who crossed his path, creating fierce tigers to carry out his wrath. The mortal turned out to be a beautiful young woman, Amethystos, who was on her way to pay tribute to Artemis. Her life is spared by Artemis, who transformed the maiden into a statue of pure crystalline quartz to protect her from the brutal claws. Dionysus wept tears of wine in remorse for his action at the sight of the beautiful statue. The god’s tears then stained the quartz purple.

Amethyst is produced in abundance from the state of Minas Gerais in Brazil where it occurs in large geodes within volcanic rocks. It is also found and mined in South Korea. The largest opencast amethyst vein in the world is in Maissau, Lower Austria. Many of the hollow agates of Brazil and Uruguay contain a crop of amethyst crystals in the interior. Much fine amethyst comes from Russia, especially from near Mursinka in the Ekaterinburg district, where it occurs in drusy cavities in granitic rocks.

Traditionally included as one of the most valuable gemstones, along with diamond, sapphire, ruby, and emerald, amethyst has lost much of its value due to the discovery of extensive deposits in locations such as Brazil. The highest grade amethyst called “Deep Russian” is exceptionally rare and therefore its value is dependent on the demand of collectors when one is found.

Crystalization

Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air. Frost crystal sizes differ depending on the time and water vapor available. Frost is also usually translucent in appearance.

Window frost, also called fern frost, forms when a glass pane is exposed to very cold air on the outside and moderately moist air on the inside. If the pane is not a good insulator, such as a single pane window, water vapour condenses on the glass forming patterns. The glass surface influences the shape of crystals, so imperfections, scratches or dust can modify the way ice nucleates.

Frost formation is a complex process, and conditions have to be right for it to occur. It forms on surfaces directly from the vapor state without condensing as dew. If dew forms, frost formation is unlikely, even if the temperature drops below freezing.

Frost is more likely to form on surfaces above ground first, such as house roofs, or automobiles, because the air immediately above the ground is usually a few degrees warmer than air a few feet higher. There is some heat transfer from the ground to the air a few centimeters above it. If there is wind, frost will not form. If the skies are cloudy frost will not form, as the clouds reflect the radiated heat from the ground which helps in keeping the lower layers mixed.

The ideal condition for frost formation is a night with clear skies, light winds, and a temperature forecast to be near or a little below freezing. Temperature and water vapor humidity determine the crystalline forms. Ice crystals are responsible for the artistic displays of window frost. The principal axis of a single crystal of ice is perpendicular to the axis of hexagonal symmetry, and as these crystals are formed the patterns of window frost develop.