The Technical Scientific Stuff

[Guest guest]

*The Technical Scientific Stuff*

* *

*Technical stuff About* *rocks and crystals is not my* *strong

suit. I'm just going to skim ** over a lot of* *that .*

*Our main focus here is on the mystical and healing side of

crystals but* *most of us would like know a little bit about the

more concrete side* *as well* *sometimes knowing about the origins

of a kind of stone can give us* *guidance in working with it .*

 

 

 

*Rocks can be placed in three groups for convenience :*

 

*Igneous rocks*

*Include Granite ,rhyolite, obsidian, and basalt They are formed by the

solidification of molten magma that emerges via volcanic activity and

emerges or erupts through vents or fissures in the Earth's Crust The

nature and properties of these crystals vary greatly depending in part

on the conditions under which the magma solidified . fast cooling

creates rocks that tend not to have crystals slower cooling can give

similar kinds of atoms trapped in the magma time to find each other and

form crystals . There are thousands of different kinds of igneous rocks.*

 

 

*Sedimentary rocks*

*such as limestone , sandstone, shales, halites coals, and gypsum

are formed by the accumulation of " sediments " these are fine rock

particles or fragments, skeletons of microscopic organisms, or

minerals leached from rocks that have accumulated from weathering.

These sediments have been redeposited under water and were later

compressed in layers over time and are classed as either evaporative

(often water soluble ) or organic sedimentary rocks.*

 

*Metamorphic rocks*

*such as marble, slate , schist, gneiss and quartzite are formed by the

alteration of igneous and sedimentary rocks through heat and/or

pressure . These physical and/or chemical changes to rocks maybe

exemplified by the formation of marble from thermal changes that have

occurred to limestone.*

 

*What is the difference between a rock and a mineral?*

*A mineral is defined as a substance that must have all four of these*

*characteristics: It must be found in nature. It must not be made of

anything that has ever been alive (organic). It has the same chemical

makeup wherever it is found and its atoms are arranged in regular

patterns and form crystals. It is solid.*

 

*Rocks are sometimes defined as an aggregate or combination of one or

more minerals and the definition is extended to cover clay ,loose sand

and certain limestones.*

 

*Crystal*

*a crystal is a uniform body with a geometric lattice. the varying

structures of the lattice are the causes of the varying physical

properties of the crystals and therefore also of the minerals and gems.*

 

 

 

*One way gemstones are classified is by hardness, both scratch hardness

and cutting resistance while the Mohs scale of hardness developed by

Frederich Mohs (1773-1839) is made somewhat obsolete by modern

technology an idea of the general hardness of a stone and whether it is

brittle helps you to protect your stones from damage and can help with

identification from softest to hardest the Mohs scale*

*1 Talc*

*2 Gypsum*

*3 Calcite*

*4 Fluorite*

*5 Apatite*

*6 Orthoclase*

*7 Quartz*

*8 Topaz*

*9 Corundum*

*10 Diamond*

 

*.*

*Piezoelectricity is that quality by which electricity and sometimes

light is produced by compression . Many cultures and spiritual

traditions have used crystals in ritual, often striking them to produce

flashes of visible light.*

*Pyroelectricity is that quality of an electrified state or polarity

which is produced by variation in temperature. Quartz has both

piezoelectric and pyroelectric properties which means that the

polarity of quartz crystal will change when subject to pressure or

heat as well as when held.*

 

*Crystal Terminology*

 

* Asterism*

*Shining lines that cross one another like rays from a star, caused by*

*light reflected by a series of microscopic canals.*

 

* Chatoyancy*

* Bands of light and dark that vary in width and hue as the stone is

turned in the light.*

 

* Cleavage*

* A mineral's tendency to split when force is applied, leaving a flat*

*surface. This happens when there are layers of weakness within the

crystal.*

 

* Cryptocrystalline*

*Composed not of a single crystal crystal but of many extremely small*

*crystals, fused together.*

 

* Dichroism*

*The way different colors or shades can be seen according to the angle*

*at which you look at the crystal.*

 

* Double Refraction*

*Light is split into two rays, producing a double image.*

 

* Inclusion*

*Any embedded foreign body, such as rutile crystals in Quartz, or an ant

in Amber.*

 

* Labradorescence*

* The colorful play of refracted light reflected from cleavage planes.*

 

* Optical Lens*

* Refracted light is bent so as to enlarge, reduce, invert, or otherwise

distort an image.*

 

 

 

*( Some of this is adapted from " The Handy Science Answer Book " and from*

*package notes from several little rock collection kits and Gemstones of*

*the world by Walter Schumann)*

 

*Solarraven ~ Peggy Jentoft*