Geodes- a fascinating geological wonder.

Chotanagpur Plateau of Jharkhand State of India contains numerous varieties of geodes.

by

Dr. Nitish Priyadarshi

They are a fascinating geological wonder. From the outside, they appear as any common, ugly rock, but when broken open they reveal a charming display of crystals. Practically all geodes are composed of Quartz. The crystals can be microscopic or can be quite large. When it occurs in crystals not visible to the human eye, it is known as a Chalcedony Geode

Geodes are the discrete bodies of mineral matter, commonly spherical, hollow, and lined inside with crystals of various minerals. Geodes necessarily originate from cavities in rock. Deposition of minerals proceeds inward from the cavity wall, producing a characteristic drusy structure, so that the youngest mineral generation is near the center and may fill the void completely. In a geode, the mineral layers lining the cavity must be more resistant to weathering and erosion than the host rock, so that upon weathering, a discrete, hollow mineral body is released.

Any cavity in rock is potentially the site of geode formation. In a particular geode occurrence, the key question is the origin of the cavity. Geodes have formed in vesicles of lava flows, such as those of the Columbia Plateau. Miarolitic cavities in plutonic igneous rocks, the original voids or body cavities of fossils, and a host of solution cavities in sedimentary rocks have given rise to geodes. The origin of the geodes involves first the origin of the cavity, and second the filling of the cavity.

Significant features of geodes are their sub-spherical shape, their hollow interior, their outer chalcedonic layer and, the inner drusy lining of inward projecting crystals.
Geodes are hollow, globular bodies, varying from couple of centimeters to nearly a meter in diameter (most are 10 to 20 cm).

The mineral matter that fills the cavities comes from ground water passing through the rock. Water contains dissolved matter such as silicon, oxygen, calcium, and carbonate. Under certain conditions, these chemicals precipitate out of the water, forming a solid mineral that is deposited inside the cavities. (This is the same manner in which lime builds up on a stalactite , or on the inside of a tea pot.) One of the most common types of mineral matter filling nodules and geodes is silica, in the form of agate.

Each geode is unique in composition and can only be truly discovered when cracked open or cut with a rock saw. The size and formation of crystals and different shades of color within the crystals make each geode special.

Chotanagpur Plateau of Jharkhand State of India contains numerous varieties of geodes. Villagers sometime confuse it with diamonds filling in rocks.

Mineralogy:

Most geodes have siliceous outer shells; the physical and chemical durability of silica is responsible for the discreteness and preservation of such geodes. Geodes with outer shells of calcite or iron oxides and hydroxides are less common. Some contain clear, pure quartz crystals, and others have rich purple amethyst crystals. Still others can have agate, chalcedony, or jasper or minerals such as calcite, dolomite, celestite, etc. There is no easy way of telling what the inside of a geode holds until it is cut open or broken apart.

Sources:

1. Pettijohn, E.J., 1984. Sedimentary Rocks. CBS Publishers, India.
2. The Encyclopedia of Sedimentology, 1978. ed. Rhodes W. Fairbridge and Joanne Bourgeois. Dowden, Hutchinson & Ross, Inc. Pennsylvania.

Fluoride toxicity in Jharkhand State of India- People eating Chakwad plants are less affected.

Fluoride toxicity in Jharkhand State of India- People eating Chakwad plants are less affected.
By
Dr. Nitish Priyadarshi

Tragedy has struck many a family in the Bakhari and Chukru, village of Jharkhand's Daltanganj district, where excess fluoride in water has left several with severe physical deformities and even paralyzed some.
Bakhari village, situated about 20 km from the district headquarters, has a population of nearly 700, comprising mostly tribals and members of socially underprivileged groups. Two-thirds of the villagers have reportedly developed physical deformities as all the sources of drinking water in Bakhari have excess fluoride content.
Residents of the remote village of Chukru, are experiencing various physical disabilities due to the presence of excessive fluoride in the ground water of the area. Every second person - children as well as adults - is suffering from deformed limbs, cataract, or premature ageing. Fluorosis hit the village in 1980 when the Government constructed borewells here to solve the drinking water problem of the village. A boon soon became a curse.

Bakhari residents draw water from 30 wells and six hand pumps in the village, all of which have excess fluoride. Without alternative sources of water, they are forced to continue using water from the contaminated wells and pumps.
According to sources in the Singhbhum and Seraikela-Kharsawan, district of Jharkhand fluoride and iron have been detected above the permissible limit in underground water in some areas.

According to the recent report people especially tribal consuming Chakwad (ring worm plant) plant are less affected of fluoride toxicity. Chakwad plants are consumed by the local tribal people in believe that it keeps them healthy. Without knowing that it is also helping them to minimize fluoride contamination they regularly eat Chakwad plant with other daily foods. According to the report those people who are not eating this plant are more affected with fluorosis. In Madhya Pradesh, the promotion of Chakwad (Cassia tora), which is rich in calcium, has helped mitigate the disease.
Main cause behind this effect is the presence of high calcium in this plant. Calcium , binds fluorine --assisting in safe excretion of fluorine, and also helping replenish body calcium stores depleted by fluorine.
It is similar to Stellaria spp. (common chickweed) which is generally used as a tea. This plant, a common garden weed which is edible in apparently unlimited quantities without toxic effect. It can be used as a vegetable and in green drinks. It is rich in Vitamin. C and in minerals, especially calcium, magnesium, and potassium.
Other Calcium-rich herbs include nettle, sage, chickweed, red clover, comfrey leaf, and raspberry leaf. A tasty infusion of any one or a combination of these herbs every day should be taken.
According to the different research reports, to minimize fluoride in the body one should eat plenty of foods that are high in calcium and vitamin D. Good sources of easily assimilable calcium include broccoli, chestnuts, clams, dandelion greens, most dark green leafy vegetable (see above), flounder, hazelnuts, kelp, molasses, oats, oysters, salmon, sardines (with the bones), sea vegetables, sesame seeds, shrimp, soybeans, tahini (sesame butter), tofu, and wheat germ. Include garlic and onions in the diet.
The Chakwad plants are very common in Jharkhand. People are not aware of the quality of these plants of minimising fluoride from the body.
Chakwad plant is found in warm moist climatic conditions and is generally found in tropical region where sun rays fall directly, it is also seen in areas where rains are in excess. It is found everywhere in India especially middle and south India.
It is an annual small plant that attains a maximum height of 1 to 5 feet. Seed contains rhein, aloe-emodin and chrysophanol. It also contains nearly 7% resins. There is also certain minerals like calcium, iron and phosphorus.
It also acts in skin ailment. It also acts as nerve tonic, liver stimulant and heart tonic. It acts on cholesterol thus maintaining the normal level of cholesterol. It also act as curing the infection occurring in the body and is given in worm infestation.
Jharkhand Government should promote such types plants in Fluoride affected areas.