The shattered glass of memories that never were
The feeling of your arms holding me
Just a faded memory of times that never were

The blame on me
Deserved like a murderer's death
When I thought I had you in my grasp
The only place I could find you was in my heart
When I looked to find myself
I looked to you and all I could see were images of her
I wasn't to be found
So I looked to the stars
I looked for a glimps of what could be
What I am, or what I was
And all I saw were the lovers of the world
Shimmering bright.. with their happiness and joy
and hope knowing they always had a heart they could take refuge in..


-- Victoria Palmer


Editor Note: Victoria Palmer is juliet. This is not a copyright issue.

glark = G = glass tty

glass n.

[IBM] Synonym for silicon.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

So, what is glass?

Glasses can be manufactured in different ways and from different materials. They can be organic, inorganic, or even metallic. As such, a glass cannot be defined by its chemical nature. All glasses have some characteristics in common though: they have an amorphous structure and, over a specific temperature range, a certain kind of behaviour that is known as glass transition. Thus, a glass is defined as an 'amorphous solid that shows a glass transition'.

Most kinds of glass that are in daily use (the kinds that you drink your beer out of, the kind that you look through when you look outside and the kind that is used in laboratory glassware), are oxide glasses. They consist of a network of (usually metallic) ions, connected by oxide ions. The prototypical oxide glass is amorphous SiO2 or fused silica.In this material the basic unit consists of a silicon ion surrounded by four oxygen ions in the shape of a tetrahedron. The oxygen ions form the bridges between the units; each 'bridging' oxygen is shared by two tetrahedral units so that the overall formule turns out to be SiO2, not SiO4 as you might suspect from the basic unit.

The presence of the 'bridging' oxygen ions makes a three-dimensional network structure possible. This kind of structure is characteristic of oxide glasses, although the shape of the basic unit may vary.

Pure fused silica has a very high melting temperature and is therefore hard to process. To remedy this, its structure is modified by adding Na2O. Each Na2O molecule reacts with the silica network by breaking up the network at the site of a bridging oxygen ion. The result is then one complete and one incomplete silica tetrahedron. The oxygen ion from the Na2O molecule fills up the space in the incomplete tetrahedron, resulting in two so-called non-bridging oxygen ions. The local excess space charge this causes is neutralized by the Na+ ion. The addition of a modifier (there are others than Na2O, although Na2O is widely used), causes the glass network to become 'looser', making processing of the glass easier. Besides that, the presence of the Na+ or similar ions makes diffusion of ions through the glass possible.

The Discovery of Glass

Glass has always been present on Earth, formed whenever certain silicon-containing rocks melt due to phenomena such as volcanic eruptions, lightning strikes or the impact of meteorites, and then cool rapidly, solidifying in the process.

Archaeologists studying the neolithic period (c. 9000 BC) have demonstrated that cutting tools made of obsidian, a dark-coloured glass of volcanic origin, may have been used widely. However, the manufacture of glass objects, initially confined to glass beads, is not thought to have commenced until at least 4000 BC, with finds in Egypt and Eastern Mesopotamia tentatively dated to this period.

Glass vessels were first produced in about 1500 BC, when Egyptian craftsmen developed a method for producing glass pots by dipping a core mould of compacted sand into molten glass. As the glass cooled and solidified, it took the shape of the core which could easily be removed later. The next major technological breakthrough in glassmaking was the discovery of glassblowing during the reign of Augustus (27 BC - 14 AD), attributed to Syrian craftsmen working in the region of Sidon, near the site of Babylon.

For centuries, the pre-eminent glass producing area in the world was the island of Murano. Here, the high quality glass which formed the basis of the Venetian trading empire was guarded with such jealousy that the traditional punishment for a glassblower revealing the secrets of his trade was death.


The Manufacture of Glass

Common glass is made from:
  • sand or silica (SiO2)
  • sodium carbonate(Na2CO3)
  • limestone (CaCO3)
  • magnesium carbonate (MgCO3)
  • additives to improve the glass quality and to colour the glass
  • At high temperatures, carbon dioxide is expelled from the sodium carbonate, producing sodium oxide(Na2O), a substance which reduces the minimum temperature at which the silica will fuse from 1700°C to about 800°C. By the same mechanism, calcium oxide (CaO) and magnesium oxide (MgO) are produced from their respective carbonates, and their presence causes the glass mixture to become insoluble in water.

    Accordingly, these materials are crushed, mixed and heated for a long period of time at high temperature to ensure that all air bubbles, which might otherwise cause flaws in the final product, are eliminated. The mixture is then quickly cooled to room temperature.


    There are four major families of glass, each a variation on the basic soda-lime glass and named after its additives.

    1. Lead-alkali glass (also called lead glass)

  • lead oxide (PbO) is used in place of calcium oxide.
  • more expensive than soda-lime glass
  • excellent electrical insulating properties
  • poor resistance to high temperatures and sudden changes of temperature.
  • used in the ceramic rings on pylons for its electrical insulation properties
  • 2. Borosilicate glass
  • appreciable resistance to high temperature or sudden changes in temperature
  • medium resistance to chemical attack
  • moderately expensive to make.
  • used for light bulbs, photochromic glasses, sealed-beam headlights, laboratory ware, and some bake-ware products.
  • 3. Alumino-silicate glass
  • alumina (Al2O3) is added to the glass batch to improve the properties of the glass.
  • good resistance to high temperature or sudden changes in temperature
  • difficult to make.
  • used in plasma display screens and optical fibres
  • 4. Fused silica glass
  • made only from silicon dioxide (SiO2) in the noncrystalline state.
  • expensive and difficult to make due to its maximal resistance to high temperature (900°C for extended periods, 1200°C for short periods).
  • used in special applications such as optical waveguides, crucibles for growing crystals.
  • Unless the raw materials are very pure, the glass produced by modern methods is green. In order to change the colour of the glass, red colourants (the complementary colour to green)must be added to allow decolourisation. The precise colour needed depends on theoxidation state of the colourant, the composition of the glass and the thermal treatment.

    In Britain "glass" can also be used as a verb to describe the action of hitting someone with a glass object such as a bottle so that it shatters on impact and cuts them to ribbons. Alternately, the object can be broken prior to the fight on a wall or other surface. The target is usually the head, and when someone is said to have "been glassed", it is usually assumed that they have been cut across the face or head.

    eg: "Did you hear what happened to Davey? Some bastard glassed him last night!"

    Glassing is a despicable act reserved for those not brave enough to have a "proper" fight, or just plain nutcases. The weapon of choice for glassing is, well, a pint glass. A regional variation is bottling.

    Lead Glass
    Also known simply as Crystal, is glass containing at least 24% lead oxide. While being the most expensive of glass types, it is also considered the prettiest and most durable. Full lead crystal is soft and malleable which makes it ideal for heavy cuttings and engravings. Few things at all relating to food, if any, is made with full lead glass.
    A reasonable alternative to full lead glass is part lead glass, commonly known as Cristellin. Regrettably, it’s not quite as brilliant or durable as full lead crystal. It has very little lead content (between 6% and 10%), it is accordingly less expensive with many of the same characteristics.

    Kali Glass
    Kali glass, which is also known as potash glass, is used for making stemware and barware. Due to the health risks associated with lead, many glass factories go out of their way to achieve the characteristics of lead glassware without adding lead. I remember my grandparents talking about glassware and being terrified that they might get lead poisoning from it. Thanks to Kali glass we can feel safe buying hot-looking glassware, with shapes and designs as leaded glass.

    Recycled Glass
    So THIS is where all those bottles go. Not surprisingly, recycled glass is traditionally blue and green. Broken glass for remelting, also known as cullet, makes up the largest percentage of the glass mix, which gives the glass its color. It can be hand-blown or machine made. Bubbles are sometimes a common, charming addition to this type of glass, they are called seeds.

    Soda Glass
    This is a dull, brittle glass that contains no lead. Soda is added to the mixture to speed melting and solidification (much like the process used to make crack cocaine). The glass is composed of 50% silica (sand), 30% soda, 10% potash and 10% lime. Soda glass can be made in a machine and it can also be hand-blown.

    Glass (?), n. [OE. glas, gles, AS. glaes; akin to D., G., Dan., & Sw. glas, Icel. glas, gler, Dan. glar; cf. AS. glaer amber, L. glaesum. Cf. Glare, n., Glaze, v. t.]

    1.

    A hard, brittle, translucent, and commonly transparent substance, white or colored, having a conchoidal fracture, and made by fusing together sand or silica with lime, potash, soda, or lead oxide. It is used for window panes and mirrors, for articles of table and culinary use, for lenses, and various articles of ornament.

    ⇒ Glass is variously colored by the metallic oxides; thus, manganese colors it violet; copper (cuprous), red, or (cupric) green; cobalt, blue; uranium, yellowish green or canary yellow; iron, green or brown; gold, purple or red; tin, opaque white; chromium, emerald green; antimony, yellow.

    2. Chem.

    Any substance having a peculiar glassy appearance, and a conchoidal fracture, and usually produced by fusion.

    3.

    Anything made of glass

    . Especially: (a)

    A looking-glass; a mirror

    . (b)

    A vessel filled with running sand for measuring time; an hourglass; and hence, the time in which such a vessel is exhausted of its sand

    .

    She would not live The running of one glass. Shak.

    (c)

    A drinking vessel; a tumbler; a goblet; hence, the contents of such a vessel; especially; spirituous liquors; as, he took a glass at dinner

    . (d)

    An optical glass; a lens; a spyglass; -- in the plural, spectacles; as, a pair of glasses; he wears glasses

    . (e)

    A weatherglass; a barometer

    .

    Glass is much used adjectively or in combination; as, glass maker, or glassmaker; glass making or glassmaking; glass blower or glassblower, etc.

    Bohemian glass, Cut glass, etc. See under Bohemian, Cut, etc. -- Crown glass, a variety of glass, used for making the finest plate or window glass, and consisting essentially of silicate of soda or potash and lime, with no admixture of lead; the convex half of an achromatic lens is composed of crown glass; -- so called from a crownlike shape given it in the process of blowing. -- Crystal glass, ∨ Flint glass. See Flint glass, in the Vocabulary. -- Cylinder glass, sheet glass made by blowing the glass in the form of a cylinder which is then split longitudinally, opened out, and flattened. -- Glass of antimony, a vitreous oxide of antimony mixed with sulphide. -- Glass blower, one whose occupation is to blow and fashion glass. -- Glass blowing, the art of shaping glass, when reduced by heat to a viscid state, by inflating it through a tube. -- Glass cloth, a woven fabric formed of glass fibers. -- Glass coach, a coach superior to a hackney-coach, hired for the day, or any short period, as a private carriage; -- so called because originally private carriages alone had glass windows. [Eng.] Smart.

    Glass coaches are [allowed in English parks from which ordinary hacks are excluded], meaning by this term, which is never used in America, hired carriages that do not go on stands. J. F. Cooper.

    -- Glass cutter. (a) One who cuts sheets of glass into sizes for window panes, ets. (b) One who shapes the surface of glass by grinding and polishing. (c) A tool, usually with a diamond at the point, for cutting glass. -- Glass cutting. (a) The act or process of dividing glass, as sheets of glass into panes with a diamond. (b) The act or process of shaping the surface of glass by appylying it to revolving wheels, upon which sand, emery, and, afterwards, polishing powder, are applied; especially of glass which is shaped into facets, tooth ornaments, and the like. Glass having ornamental scrolls, etc., cut upon it, is said to be engraved. -- Glass metal, the fused material for making glass. -- Glass painting, the art or process of producing decorative effects in glass by painting it with enamel colors and combining the pieces together with slender sash bars of lead or other metal. In common parlance, glass painting and glass staining (see Glass staining, below) are used indifferently for all colored decorative work in windows, and the like. -- Glass paper, paper faced with pulvirezed glass, and used for abrasive purposes. -- Glass silk, fine threads of glass, wound, when in fusion, on rapidly rotating heated cylinders. -- Glass silvering, the process of transforming plate glass into mirrors by coating it with a reflecting surface, a deposit of silver, or a mercury amalgam. -- Glass soap, ∨ Glassmaker's soap, the black oxide of manganese or other substances used by glass makers to take away color from the materials for glass. -- Glass staining, the art or practice of coloring glass in its whole substance, or, in the case of certain colors, in a superficial film only; also, decorative work in glass. Cf. Glass painting. -- Glass tears. See Rupert's drop. -- Glass works, an establishment where glass is made. -- Heavy glass, a heavy optical glass, consisting essentially of a borosilicate of potash. -- Millefiore glass. See Millefiore. -- Plate glass, a fine kind of glass, cast in thick plates, and flattened by heavy rollers, -- used for mirrors and the best windows. -- Pressed glass, glass articles formed in molds by pressure when hot. -- Soluble glass Chem., a silicate of sodium or potassium, found in commerce as a white, glassy mass, a stony powder, or dissolved as a viscous, sirupy liquid; -- used for rendering fabrics incombustible, for hardening artificial stone, etc.; -- called also water glass. -- Spun glass, glass drawn into a thread while liquid. -- Toughened glass, Tempered glass, glass finely tempered or annealed, by a peculiar method of sudden cooling by plunging while hot into oil, melted wax, or paraffine, etc.; -- called also, from the name of the inventor of the process, Bastie glass. -- Water glass. Chem. See Soluble glass, above. -- Window glass, glass in panes suitable for windows.

     

    © Webster 1913.


    Glass, v. t. [imp. & p. p. Glassed (?); p. pr. & vb. n. Glassing.]

    1.

    To reflect, as in a mirror; to mirror; -- used reflexively.

    Happy to glass themselves in such a mirror. Motley.

    Where the Almighty's form glasses itself in tempests. Byron.

    2.

    To case in glass.

    [R.]

    Shak.

    3.

    To cover or furnish with glass; to glaze.

    Boyle.

    4.

    To smooth or polish anything, as leater, by rubbing it with a glass burnisher.

     

    © Webster 1913.

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