4C (21) Tsang Suet Ying's ans: This is because hematite is Iron (III) oxide which is red in colour. It' s original form is iron. When iron contacts with the air and water, rusting and oxidizing occur. It becomes hematite, so that we can see the red colour.
Lo Hiu Tung: I don't know the formation of diamonds.
4C (21) Tsang Suet Ying's ans:
The information is come from a website.[1]
Diamonds are formed when heat reaches a certain temperature in combination with a certain pressure being reached which only occurs at 75 to 120 miles below the earth's surface. It was commonly believed by many that diamonds were formed as a metamorphism of coal. The belief now is that temperature changes in the upper mantle of the earth causes carbon atoms to go deeper where they melt. It is believed that they shot out towards the earth's surface during volcanic activity and then settled in the pipes that were created by the force. These pipes are called Kimberley pipes and these are primary deposits. This is where miners look for diamond deposits. The diamonds that made it to river beds over time and perhaps with the help of erosion are known as alluvial deposits.
It is believed that the first delivery of these diamond deposits occurred 2.5 billion years ago. The most recent delivery was 45 million years ago. They take thousands of years to form. Their intrigue is further enhanced with the knowledge that they might be 45 million years old at least.
Reference:
[1] http://www.articlesbase.com/advice-articles/the-formation-of-diamonds-164818.html
1.Leung Ho Yee: is burying & compressing dead vegetation in swamp the only way to form coal?
4C (21) Tsang Suet Ying's ans:
More information can be found in website[1]
Yes, coal can only be formed by burying & compressing dead vegetation in swamp. Decomposition of the death of plant debris about 100 million years to 44 million years ago, so often referred to as fossil fuels. The formation of coal plants could grow in swamps or river deltas. When they die, bacteria decompose the wreckage through the decomposition of changes, gradually formed a thick layer of marsh material. In these years, these substances become harder into peat. The passage of time, peat deposition period and with the movement of the earth, making mud buried deeper underground coal, and minerals together and heat through to the role and biochemical reactions, some into sandstone or shale, increasing weight and the page level Other cover began to peat into various grades of coal, sandstone and other sediments forming the rock called sedimentary rock. The process in coal rank, the content of hydrogen, oxygen decreases while the content of carbon increases.
Reference[1]:http://hk.knowledge.yahoo.com/question/question?qid=7006072102872
2. Lo Vanessa Hiu tung: How do people find crystals?
4C (21) Tsang Suet Ying's ans:
More information can be found in website[1]
When People connect the current to the crystal, the crystal will be bulging. When we stop the current, the crystal will draw back as it is. When pass the current to the crystal again, the crystal can be a very fast, very stable to expand and contract. When the crystal is carefully cut to a certain size, length and width, thickness, the frequency of such oscillations can also be very accurate under control. So that people can find crystals
Reference[1]:http://hk.knowledge.yahoo.com/question/question?qid=7007082604534
3. Lam Lok Ting: What forms minerals?
4C (21) Tsang Suet Ying's ans:
A mineral is a naturally occurring solid chemical substance that is formedhttp://en.wikipedia.org/wiki/Mineral#Mineral_composition_of_rocks
through geological processes and that has a characteristic chemical
composition,
a highly ordered atomic structure, and specific physical
properties. By
comparison, a rock is an aggregate of minerals and/or
mineraloids and does not
have a specific chemical composition. Minerals
range in composition from pure
elements and simple salts to very complex
silicates with thousands of known
forms.
7. To Tsz Ching: Why are rocks and minerals important for us?
4C (21) Tsang Suet Ying's ans:
Minerals can make cosmetic, such as base. Moreover, minerals can make many different kinds of jewelry. For example, Agate. Chinese people think that wear Agates not only for decoration, they can make our mind clear and improve efficiency. So Agate is one of the most popular products in China. Also, many Feng Shui products are made by minerals. Rock is important too because it can make furniture, e.g. chairs in parks.
9. Chung Yuen Shan: Which minerals form limestone?
4C (21) Tsang Suet Ying's ans:
Limestone is a sedimentary rock composed largely of the mineral calcite (calciumhttp://en.wikipedia.org/wiki/Limestone
carbonate: CaCO3). Like most other sedimentary rocks, limestones are composed of
grains; however, most grains in limestone grains are skeletal fragments of
marine organisms such ascoral or foraminifera. Other carbonate grains comprising
limestones are ooids, peloids, intraclasts, and extraclasts. Some limestones do
not consist of grains at all and are formed completely by the chemical
precipitation of calcite or aragonite. i.e. travertine.
10. Lai Yin Sum: What is the factor affecting the color of rocks?
4C (21) Tsang Suet Ying's ans:
The color of rocks id affected by the minerals the rocks contained.
14. Ho Wing Man: How can wind affect the formation of sedimentary rocks?
4C (21) Tsang Suet Ying's ans:
More information can be found in website[1]
Weathering breaks the rocks into debris, or other biological remains. Then through erosion, sedimentation, and petrochemical, and other effects caused by the rock. Old age rocks were first deposited in the lower part; the more the level of those, then the more new age, which is called the overlay layer of rules. When sedimentary rocks often contain organisms when buried also, after a long life time can be preserved to become fossils; in igneous rocks there are more non-fossil.
Reference[1]:http://hk.knowledge.yahoo.com/question/question?qid=7007061701711
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