Forums
New posts
Search forums
What's new
New posts
Latest activity
Members
Registered members
Current visitors
Charts
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Gold Prospecting
Metal Detecting for Gold
What Is/Was Pipeclay And How Is It Formed?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Help Support Prospecting Australia:
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Message
<blockquote data-quote="user 4386" data-source="post: 630888" data-attributes="member: 4386"><p>You are quite correct - it is usually what is commonly called kaolin (the mineral kaolinite).</p><p></p><p>The physical properties of clays and the uses they can be put to varies with their mineralogy. Kaolinite has many uses because it is the main component of good quality pottery clay and can be fired to a fine-grained uncoloured (white) hard finish as in fine quality white china - although you can add ochres to colour it.</p><p></p><p>For example, during weathering a basalt or shale might become smectite clay (which contains things like sodium, calcium, iron and magnesium in it) - it has its uses, such as in filtering oils. This is an expanding clay and fires to an dirty finish. More weathering and the iron and magnesium leaches out but any potassium remains (or more commonly a clay forms from a potassium-rich shale), to become illite clay. Even more weathering and it loses its potassium and becomes kaolinite, a pure hydrated aluminium silicate. The other clays have their uses - eg we usually don't try to make bricks out of kaolinite but out of a more illite-rich mixture, preferably with some iron oxide mixed with it to give it a nice red colour when fired. You may have noticed that a lot of cream-brick houses were built in the 1950s. This was because in the post war building boom, they could not find enough iron-oxide stained clay.</p><p></p><p>Horses for courses.</p><p></p><p><a href="https://geologyscience.com/minerals/clay-minerals/" target="_blank">https://geologyscience.com/minerals/clay-minerals/</a></p></blockquote><p></p>
[QUOTE="user 4386, post: 630888, member: 4386"] You are quite correct - it is usually what is commonly called kaolin (the mineral kaolinite). The physical properties of clays and the uses they can be put to varies with their mineralogy. Kaolinite has many uses because it is the main component of good quality pottery clay and can be fired to a fine-grained uncoloured (white) hard finish as in fine quality white china - although you can add ochres to colour it. For example, during weathering a basalt or shale might become smectite clay (which contains things like sodium, calcium, iron and magnesium in it) - it has its uses, such as in filtering oils. This is an expanding clay and fires to an dirty finish. More weathering and the iron and magnesium leaches out but any potassium remains (or more commonly a clay forms from a potassium-rich shale), to become illite clay. Even more weathering and it loses its potassium and becomes kaolinite, a pure hydrated aluminium silicate. The other clays have their uses - eg we usually don't try to make bricks out of kaolinite but out of a more illite-rich mixture, preferably with some iron oxide mixed with it to give it a nice red colour when fired. You may have noticed that a lot of cream-brick houses were built in the 1950s. This was because in the post war building boom, they could not find enough iron-oxide stained clay. Horses for courses. [url]https://geologyscience.com/minerals/clay-minerals/[/url] [/QUOTE]
Verification
Post reply
Gold Prospecting
Metal Detecting for Gold
What Is/Was Pipeclay And How Is It Formed?
Top