# conchoidal

3

A curve with polar coordinates,

(1)

studied by the Greek mathematician Nicomedes in about 200 BC, also known as the cochloid. It is the locus of points a fixed distance away from a line as measured along a line from the focus point (MacTutor Archive). Nicomedes recognized the three distinct forms seen in this family for , and . (For , it obviously degenerates to a circle.)

The conchoid of Nicomedes was a favorite with 17th century mathematicians and could be used to solve the problems of cube duplication,angle trisectionheptagon construction, and other Neusis constructions (Johnson 1975).

In Cartesian coordinates, the conchoid of Nicomedes may be written

(2)

or

(3)

The conchoid has  as an asymptote, and the area between either branch and the asymptote is infinite.

This is all according to Wolfram. See Wolfram’s website for more details.

Snail..:) #macro #micro #Sony #xperia #macrophotography #snail #conchoidal #slow #moving #instagram #pictureoftheday #instapic #instalike

2

I colored her!
And oops, I really like her a lot.
I need to draw her weapon at some point though, and how it works because I think it’s kind of cool.

Anyway! I’m kind of a geology nerd, so I figured I share some stuff about Moonstone. It kind of got a bit long because I like rocks, sorrynotsorry.

Moonstone is a type of feldspar, which is high in silica meaning it forms when lava cools. It’s specifically formed when two types of feldspar, orthoclase and albite, mix together before cooling.

It has a hardness level of 6, which makes it a fairly hard mineral just below Quartz and can only be scratched by steel or something harder.

Also, it cleaves conchoidally, which means that it doesn’t break evenly on any plane.

Chemical Sedimentary Rock

•Chemical sedimentary rocks such as rock salt and some limestones, that form when dissolved materials precipitate from solution

## Iron Ore

Earth’s most important iron ore deposits are found in sedimentary rocks. They formed from chemical reactions that combined iron and oxygen in marine and fresh waters. The two most important minerals in these deposits are iron oxides: hematite (Fe2O3) and magnetite (Fe3O4). These iron ores have been mined to produce almost every iron and steel object that we use today

Chert (Flint)

•Chert is a microcrystalline or cryptocrystalline sedimentary rock material composed of silicon dioxide (SiO2). It occurs as nodules, concretionary masses and as layered deposits. Chert breaks with a conchoidal fracture, often producing very sharp edges. Early people took advantage of how chert breaks and used it to fashion cutting tools and weapons.  Dark varieties of chert are common and are often called “flint”.

## Rock Salt

Rock Salt is a chemical sedimentary rock that forms from the evaporation of ocean or saline lake waters. It is also known by the mineral name “halite”. It is rarely found at Earth’s surface, except in areas of very arid climate. It is often mined for use in the chemical industry or for use as a winter highway treatment. Some halite is processed for use as a seasoning for food.