Latest Muscovite Stories
By Rakovan, John The very first Word to the Wise column dealt with the term pegmatite (Rakovan 2003). This was especially fitting because pegmatites are one of the most important rock types or geologic environments for the production of beautiful and interesting mineral specimens.
The mica group of 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...
Muscovite, also known as potash mica, is a phyllosilicate mineral of aluminium and potassium. It has a highly perfect basal cleavage yielding remarkably thin laminae (sheets), which are often highly elastic. Muscovite has a hardness of 2 - 2.25 and a specific gravity of 2.76 - 3. It can be colorless or tinted through grays, browns, greens, yellows, or rarely violet or red, and can be transparent or translucent. The green form is called Fuchsite, KAl2(AlSi3O10)(F,OH)2. Muscovite is the most...
- A handkerchief.
- Specifically— The legendary sweat-cloth; the handkerchief of St. Veronica, according to tradition miraculously impressed with the mask of Christ; also, the napkin about Christ's head (Johu xx. 7).
- In general, any miraculous portrait of Christ.