2006-12-06 12:01:52 · 5 answers · asked by Anonymous in Education & Reference ➔ Primary & Secondary Education
It is a mineral that has built up into rock, sometimes called fool's gold. It looks like a chunk of gold, but it isn't. So, Its name means brilliant, or shine. Also, it is resistant to heat. People using have been using mica for many thing since pre-historic times (cave man times, basically)
2006-12-06 12:04:14 · answer #1 · answered by hj 3 · 0⤊ 1⤋
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms.
The word "mica" is thought to be derived from the Latin word micare, meaning to shine.
Chemically micas can be given the general formula:
X2Y4-6Z8O20(OH,F)4
in which X is K, Na, or Ca or less commonly Ba, Rb, or Cs
Y is Al, Mg or Fe or less commonly Mn, Cr, Ti, Li, etc
Z is chiefly Si or Al but also may include Fe3+ or Ti
Structurally the micas can be classed as di-octahedral (Y = 4) and tri-octahedral (Y = 6). Also if the X ion is K or Na the mica is a common mica whereas if the X ion is Ca the mica is classed as a brittle mica.
2006-12-06 12:12:56 · answer #2 · answered by Enrique 2 · 0⤊ 0⤋
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms.
The word "mica" is thought to be derived from the Latin word micare, meaning to shine, in reference to the brilliant appearance of this mineral (especially when in small scales).
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2006-12-06 18:39:08 · answer #3 · answered by ? 3 · 0⤊ 0⤋
Hi. Mica is a material made of very thin layers of clear crystals. It looks like a book and can be broken apart into very thin pieces. It does nor conduct electricity and is used for electric insulation. There are some pictures on this site : http://www.answers.com/main/ntquery?s=mica&gwp=16
2006-12-06 12:05:16 · answer #4 · answered by Cirric 7 · 1⤊ 0⤋
check out http://en.wikipedia.org/wiki/Mica, and you'll find everything your six grader needs to know about mica
2006-12-06 12:27:25 · answer #5 · answered by moon 1 · 0⤊ 0⤋