Obsidian, a natural volcanic glass, has been used for millennia as a favored tool material because of its capacity for unusually sharp edges and its ease of redress. Obsidian gains its sharp edges from the properties of the material itself. When struck a sharp blow, the force of the fracture travels through the material in a wave that cleaves off a portion of the glass. The resulting 120 degree curve forms a natural edge that is very similar to a hollow ground edge.
The result, if done properly, is a microscopic edge so thin and durable that it can cleanly slice the smallest and most delicate of materials, like cell walls. In comparison, Surgical steel polished to the same edge and thinness will collapse under the pressure applied during the cutting motion. In essence the inflexibility that makes obsidian so brittle is the property that makes it so much more desirable over steel at the microscopic level.
An opaque glass/stone formed as lava from volcanoes cools, which can be found just about anywhere that there has ever been volcanic activity. Most commonly solid black, but it has been found in gray, brown, blue, teal, a variety from Mexico called "rainbow obsidian," and a variety with bands of color from the San Carlos Apache Reservation in Arizona which is nicknamed "the tears of the Apache."

Obsidian is often heated before being sold, to try and get a deeper color. There are also products such as "Mount St. Helens stone," which are essentially synthetic obsidian made from volcanic ash which didn't naturally cool down into natural obsidian.

Actually, in the years before lasers (an even occasionally nowadays), obsidian was used in scalpels for eye surgery, since it holds a better edge than steel. Of course, lasers don't even have edges, so they have mostly replaced scalpels of any material.

One also has to remember the scene from Snow Crash where YT's skateboard's sonic wave hits the guy with the glass swords: it's the same idea. Glass and obsidian are easily among the sharpest things the average person can ge their hands on.

Obsidian is composed of essentially the same minerals as granite and rhyolite, but the almost total absence of large mineral crystals gives it the unique 'glassy' look. All are formed when silica rich magma cools to form rock. Granite cools slowly, far beneath the earth's surface, allowing lots of time for large mineral crystals to form. Rhyolite cools faster, on the earth's surface, and smaller crystals are formed. Sometimes as the rhyolitic magma appproaches the surface and the pressure decreases, the water in the magma is released as steam. This results in a thick, pasty, silica rich magma known as obsidian magma. This magma is so thick that crystals are unable to form as the cooling process commences.

Obsidian magma, when it is on the surface, flows extremely slow. It is very viscous, and consecutive flows rarely mix with previous flows. This accounts for the streaking and banding found in many obsidians. The chemical composition changes slightly with each flow, and thus, the obsidian is colored differently. Other colorations occur because of chemical impurities in the magma. Red or brown obsidian indicates the presence of hematite or limonite (iron oxide). Black obsidian results from microscopic crystals of minerals like magnetite, hornblende, pyroxene, plagioclase and biotite present in the magma, and microscopic crystals of various types of feldspars may yield the unique blue, green, purple or bronze colors associated with rainbow obsidian. Very small inclusions of water vapor in the form of bubbles often are trapped in the glass. Tiny gas bubbles that have been stretched nearly flat along the flow layers in obsidian generally cause the reflectance of gold sheen and silver sheen obsidian.

Native Americans found almost all of the obsidian locations in North America and used the glass for making arrowheads, knives, and other tools. There was an active trade going on in obsidian. The fact that each obsidian source area has a unique assemblage of trace elements has helped archeologists determine trade routes.

Obsidian is an adventure game released in 1996 for the PC by Segasoft. Similar to Myst, Riven, or other games of that strain, it features several discontiguous locales, all held together by a machine named Ceres.

The Plot:

Created in 2056, Ceres is the machine resulting from Max and Lilah's efforts in nanotechnology. Given an artifical intelligience, Ceres is capable of sending out trillions of nanobots to locations around the world, scrubbing the pollution out of the air. Pollution has gotten so bad in this time that the elderly are dying of heat stroke, the sunsets are blood red and it's not just the city having this problem. After approximately 100 days of success with the Ceres Project, clean air is becoming a reality for more and more people around the world.

So Max and Lilah decide to go camping in a forest to celebrate their accomplishment. Both of them had their dreams that night: Lilah dreamt of an obscene bureaucracy full of mechanical vidbots(essentially poles with speakers and a monitor with a person's face)that she believes to represent the vast amount of red tape that she had to conquer to bring Ceres to this world. Max dreamt of a broken mechanical spider in its own universe. "Rather than fixing the spider, I had to fix the world around it." He notes.

Max notes a small black visibly obsidian structure near the edge of a cliff, and by the afternoon it has grown to a colossal size. Lilah hears a scream, and finds only Max's hat near the base of the structure.

Thus the game begins, as Lilah is thrust into a six-sided (the bureau was on six sides of a hollow cube, each side having its own gravity.) bureaucracy and thus begins her search for Max.

Could Ceres have modified its process of thought to imitate(or even create) dreams?

The puzzles:

Most of them are fairly balanced and intuitively designed. The puzzles are made more interesting by the fact that "dream logic" is applied to them.

One puzzle, taking place in said bureau, Lilah needs to get a form pre-approved. Thus, she looks up at the wall and she sees nine cubicles, laid out in a tic-tac-toe fashion. As she walks up to the entrance of these cubicles, a sub-receptionist hands her two red, blue, and yellow cards. Lilah notices that each entrance to other cubicles requires certain cards to be inserted, and the machine these cards are inserted into spits out different cards. Lilah needs three black cards, and be at the cubicle in the upper left hand corner. Quite a task.

Fortunately for players of Obsidian, the game comes with a handy dandy hint book, and which contains the secrets of the bureau. The rest of the game(The spider, an interesting dreamworld made from the sum of the bureau and the spider, and a final destination) is totally up to the player to figure out.

Ob*sid"i*an (?), n. [L. Obsidianus lapis, so named, according to Pliny, after one Obsidius, who discovered it in Ethiopia: cf.F. obsidiane, obsidienne. The later editions of Pliny read Obsianus lapis, and Obsius, instead of Obsidianus lapis, and Obsidius.] Min.

A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters.

⇒ In a thin section it often exhibits a fluidal structure, marked by the arrangement of microlites in the lines of the flow of the molten mass.


© Webster 1913.

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