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They can have an average diameter 5–20 centimetres (2.0–7.9 in), [3] but can be much larger (for example, 300–370 centimetres (10–12 ft) at Silver Cliff in Colorado). Lithophysae are also related to the spherulites found in obsidians on the Italian island of Lipari , in Yellowstone National Park , and other places.
In some stones, the inclusion of small, white, radially clustered crystals (spherulites) of the mineral cristobalite in the black glass produce a blotchy or snowflake pattern (snowflake obsidian). Obsidian may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being ...
For example, snow tires which enhance traction during harsh winter driving conditions are labelled with a snowflake on the mountain symbol. [32] A stylized snowflake has been part of the emblem of the 1968 Winter Olympics, 1972 Winter Olympics, 1984 Winter Olympics, 1988 Winter Olympics, 1998 Winter Olympics and 2002 Winter Olympics. [33] [34]
Cristobalite (/ k r ɪ ˈ s t oʊ b ə ˌ l aɪ t /) is a mineral polymorph of silica that is formed at very high temperatures. It has the same chemical formula as quartz, Si O 2, but a distinct crystal structure.
Many objects in the real world, such as coastlines, are statistically self-similar: parts of them show the same statistical properties at many scales. [2] Self-similarity is a typical property of fractals. Scale invariance is an exact form of self-similarity where at any magnification there is a smaller piece of the object that is similar to ...
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Obsidian hydration dating (OHD) is a geochemical method of determining age in either absolute or relative terms of an artifact made of obsidian.. Obsidian is a volcanic glass that was used by prehistoric people as a raw material in the manufacture of stone tools such as projectile points, knives, or other cutting tools through knapping, or breaking off pieces in a controlled manner, such as ...
For example, the octahedral form is written as {111}, and the other faces in the form are implied by the symmetry of the crystal. Forms may be closed, meaning that the form can completely enclose a volume of space, or open, meaning that it cannot. The cubic and octahedral forms are examples of closed forms.