Obsidian has a lustrous sheen and a pronounced conchoidal fracture. It denotes that the fracture's top is gently curved (like a seashell). Obsidian seems to be black in color. The color of the glass is created by minute inclusions and small crystals. These particles reflect light and give the glass its dark appearance.
Obsidian is volcanic glass. Volcanoes erupt lava that solidifies almost immediately into rock, but not entirely - small bubbles of gas are trapped inside the molten mass. As these gases expand or contract with changes in temperature, the volcano shifts and cracks appear in the ground. Water washes over the cracked surface and dissolves some of the rocks, leaving silica (sand) behind. Over time, trees grow across the area where lava once flowed, creating a forest. When people cut down these trees for timber or charcoal, they often bring up obsidian fragments with their roots.
Obsidian is the name given to glass formed when lava cools quickly, before all the gas bubbles have had a chance to form bubbles. The result is clear glass with tiny particles of rock embedded within it. Although most obsidians are extremely dark gray or black, there are instances where they may come out as red, green or blue.
People have been making obsidian tools thousands of years ago. They use obsidian because it is hard, heavy, and easy to work.
Obsidian is a sort of black or dark glass that forms when lava cools. In romance novels, it is sometimes used as a fancy way of describing people's eyes, as in, "Her eyes were black and gleaming, two obsidian orbs."
Obsidian eyes are extremely hard, with a crystalline structure that no organic material can grow in. This makes them perfect for windows and mirrors. They are also very fragile, so care must be taken not to damage them when removing objects from one's eye.
In mythology, the god Poseidon was said to have had obsidian eyes. This may have been because he could see perfectly in darkness, like an owl, or it may simply have been a poetic way of saying that his eyes were hard like obsidian.
In modern culture, obsidian is often used to describe eyes that are cold and emotionless, such as Elsa's in "Frozen".
This, along with quick cooling, leads in the formation of natural glass from the lava. Because obsidian is strong, brittle, and amorphous, it breaks with sharp edges. ...
|Specific gravity||c. 2.4|
|Other characteristics||Texture: Smooth; glassy|
Smooth glass gives it a unique appearance. Obsidian is a frozen liquid with trace levels of mineral impurities. Can you see the color? Because pure obsidian is normally black, it may also be virtually white on rare occasions. Examining the optical impact of tiny gas bubbles in obsidian can reveal how it was made. The more bubbles there are, the more heat was applied to the rock when it was molten.
Obsidian is hard to work with because it's brittle and tends to break easily. It must be cut with sharp tools so any sand or other small particles that are trapped inside while the rock is still hot will become embedded in its surface. This makes obsidian useful for cutting tools such as knives and spears. It is also used as ballast in some fishing weights because it is heavy and does not absorb water like metal does.
Raw obsidian looks like smooth, grayish-blue glass. It may have inclusions (holes) from trapped gases or crystals before it was melted down into a block for working. The color of obsidian varies depending on what minerals were present in the rock when it was formed. Green obsidian results from the presence of malachite, while red obsidian is rich in garnet. Black obsidian contains no colored minerals and is known as "vacuum" obsidian because it shows no sign of having been altered by inclusion of other materials during formation of the rock.
Though obsidian is normally jet-black in color, the addition of hematite (iron oxide) provides red and brown variants, and the presence of small gas bubbles may produce a golden shine. Other varieties have dark bands or mottling in gray, green, or yellow. All these variations are due to impurities present in the rock when it forms as a result of chemical reactions between water and volcanic glass.
Obsidian is typically black, but there are many different colors that can be found within the material. Red, brown, and gold are just some of the colors that can be seen in obsidian. These colors come from minerals that are inside the rock when it forms. Sometimes these minerals are mixed together in one piece of obsidian, other times they're found separately. For example, one type of obsidian might have some red areas with white crystals inside them, while another type has red bands across a blue background.
When you look at obsidian with its black and white colors, it can seem like something out of a story book or movie. This is because most obsidian comes from very old volcanoes that are mostly made up of molten rock (magma). As this magma moves through the volcano, any particles floating in the fluid stream that contact the hot liquid surface will absorb some of the heat and become solidified into new rocks.