Agate
Moss Agate
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Stones Minerals Crystals - a glossary of lapidary and geological terms
Stone
A stone is a piece of compacted mineral(s). Stone has many and varied uses and comes in many forms and types. There are thousands of different types of stones, crystals, minerals and fossils. Stone is continuously being formed and destroyed. Historically and even today, stones are attributed by many to have mystical powers such as healing. Examples of stone would be limestone, sandstone and basalt. We generally refer to any large slab of shaped rock as stone - for example, you get stone
You have heard all the lapidary terms, - but have you seen a someone sawing, shaping and polishing a stone or a jewel?
Why not watch a lapidary in action?
Click here to see what those lapidary terms actually mean in action - watch some lapidary videos - click here
Rock
Apart from being a most excellent manifestation of music, rock also happens to be (in its spare time) a large piece of stone, or a larger geological formation of compressed minerals. - Rather like pick and mix, rocks can be made up of multiple mineralS, or just one or a few. The way those minerals are manifested can also depend upon the life that the rock has had. There are generally 3 recognised types of rock - igneous, sedimentary and metamorphic.
Igneous Rock
Igneous rock is how all rock (apart from meteorites) starts off - it comes from the molten core and crust of the earth known as magma. - This magma, which is a mish mash of molten minerals, is slooshed about under the tektonic plates, rising and falling. At some point, the pressure gets too great and the magma spews out above ground, or else, the pressure drops and the magma cools down and solidifies. Either way, once that magma has solidified, it becomes what is known as igneous rock - the word ignis coming from latin for fire. The mineral component of the rock, as well as the speed and type of cooling dictate what that rock is called and its physical structure.
Metamorphic rock
Push your finger forward and backwards along a table top for about 30 seconds. You will feel it gradually getting warmer. If you did this with something harder and pushed very hard, the wood would start to smoke and catch alight (aka oxidise) - The chemical structure would change due to the heat and the pressure.
As you know, the earth's crust is constantly shifting and changing. The earth's crust sits on vast tektonic plates which in turn float upon the molten magma. These plates push each other around, ride up and down over each other - Multiply the heat and the pressure generated by your finger and the table by a billion trillion times and begin to think of what this might do to rocks. Nomatter how hard or dense a rock is, this sort of pressure and heat will cause it to change. The reaction may be a checimal one, it may be a physical one, but rest assured, it will change its form. The pressure and temperature, if they do not melt the rock, will cause it to metamorphose, the mineral structure and content will change and it will become a different type of rock. It is not really a surpise that these types of rocks are called metamorphic rocks is it, after all the word comes from the greek meta and morphe meaning to change form. - So a metamorphic rock is one that gives up under pressure!
Sedimentary rock
Well, here sits the proud piece of rock, formed from molten magama, squashed when the mountain was being formed and pressured into its proud new structure. Now for the first time, it is exposed to the air. - The rock sits there feeling rather grand - it is on top of the world and it is so hard that nothing can hurt it...
Over the next few hundred years, the ice wind and rain begin to slowly chip away at the once proud piece of rock.The little pieces are gradually washed down into the river, which then carries them out to sea. Over the next million years this continues to happen, and our once proud mountain is no more. All of it's constituent rocks have been washed away and deposited on the seabed in a layer of sand. Over millions more years more and more sand settles,and the pressure begins to build, compressing the sand into a layer of.... yes you've guessed it, rock - a sedimentary rock. Why is it called sedimentary? - because sedimentary comes from the latin for layering, as it forms in layers.
lapidary
Lapidary is the act of cutting, shaping and polishing stone. Stone tumbling is a form of lapidary. Stone tumbling is carried out by putting a number of smaller semiprecious stones or crystals into a stone tumbler, along with some grit. The mixture is then tumbled for a period of days or weeks and the stones then come out looking polished.
minerals
A mineral is a naturally occurring non organic substance with a defined chemical formula that has been formed by geological activity. Therefore, minerals are the basic constituent of all rocks, stones and crystals.
crystals
A crystal is a solidified mineral that has been geologically formed into a specific and regular atomic structure known as crystalline. Examples of crystals would be amethyst, quartz, diamond and sugar.Most gemstones are in fact crystal
Precious Stones
What is the difference between semi precious stones and precious stones ?
The fundamental difference between a semi precious stone and a precious stone is how much people have to pay for them. Historically, precious stones such as diamond and rubies were very difficult to obtain and their aquisition became a status symbol. Thus their price increased, which increased their desirability and enhanced status even further.
Stone Jewellery, Stone Jewelry - Why buy it?
The truth is that stone jewellery can look absolutely stunning. You don't actually need precious or semi precious stones to have beautiful jewellery. There are many beautiful stones that can be tumbled, cut or ground from rough rock into striking jewellery. Rose quartz, mahogonay obsidian snowflake obsidian, onyx, jasper, moonstone, agate to name but a few types of stone that can look stunning on a necklace of bracelet.
Hobby Stone Tumbling
Lapidary - Cutting facets in precious stones? Whilst the art of lapidary for cutting facets into precious stones is a very skilled craft, the arts of stone tumbling and cabouchon cutting (cutting and grinding rough rough) is a craft open to beginners.
You can start Stone Tumbling for less than £50 or $100.
You can buy a stone tumbler for under $100. You can find your own stones down at a beach, in your garden - just buy a bag of rough gravel and look closely.
It is amazing how once you start to tumble your first stones , every piece of rough rock on the ground becomes interesting. You will find yourself picking up and examining stones wherever you are , and keeping loads in your pockets too.
Once you have started down the stone tumbling trail you will begin to appreciate that all stones are different. You will find youself becoming interested in geology and you will start to read up on different types of stones!
Beware - The Stone Tumbling and Lapidary bug will get you!!! and within a couple of years you will have chosen your holiday destination on the types of rocks you want to see. You will have made some stone jewellery and you will have given someone some tumbled stones for a present!! - Just wait and see.....
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