MAGNESITE Idongesit Udofia, group 3. Scientific adviser is Evgenia Grabovetskaya

MAGNESITE

Idongesit Udofia, group 3. Scientific adviser is Evgenia Grabovetskaya

Magnesite occurs in two distinct physical forms macro crystalline and cryptocrystalline or amorphous magnesite. It also occurs in 4 different ways

1) A replacement mineral in carbonate rocks.

2) An alteration product in ultramafic rocks [igneous rocks composed mainly of one or more dark coloured ferromagnesian mineral].

3) A sedimentary rocks.

4) As nodules formed in a lacustrine environment.

Magnesite can be formed via talc carbonate metasomatism of peridotite and other ultrabasic rocks. Magnesite is formed via carbonation of olivine in the presence of water and carbon dioxide at elevated temperatures and high pressures typical of the greenschist facies. Magnesite can also be formed via the carbonation of magnesium serpentine (lizardite) via the following reaction:

Serpentine + carbon dioxide → talc + magnesite + water

2 Mg₃Si₂O₅ (OH)₄ + 3CO₂ → Mg₃Si₄O₁₀ (OH)₂ + 3MgCO₃ + H₂O.

However when performing this reaction in the laboratory, the trihydrated form of magnesium carbonate (nesquehonite) will form at room temperature. This very observation led to the postulation of a "dehydration barrier" being involved in the low-temperature formation of anhydrous magnesium carbonate. Laboratory experiments with formamide, a liquid resembling water, have shown how no such dehydration barrier can be involved. The fundamental difficulty to nucleate anhydrous magnesiumcarbonate remains when using this non-aqueousHowever when performing this reaction in the laboratory, the trihydrated form of magnesium carbonate (nesquehonite) will form at room temperature. This very observation led to the postulation of a "dehydration barrier" being involved in the low-temperature formation of anhydrous magnesium carbonate. Laboratory experiments with formamide, a liquid resembling water, have shown how no such dehydration barrier can be involved. The fundamental difficulty to nucleate anhydrous magnesium carbonate remains when using this non-aqueous solution. Not cation dehydration, but rather the spatial configuration of carbonate anions creates the barrier in the low-temperature nucleation of magnesite. Magnesite has been found in modern sediments, caves and soils. Its low-temperature (around 40 °C) formation is known to require alternations between precipitation and dissolution intervals. Magnesite in a natural form (from Lubeník in Slovakia). Magnesite was detected in meteorite ALH84001 and on planet Mars itself. Magnesite was identified on Mars using infra-red spectroscopy from satellite orbit. Controversy still exists over the temperature of formation of this magnesite. Low-temperature formation has been suggested for the magnesite from the Mars derived ALH84001 meteorite. The low-temperature formation of magnesite might well be of significance toward large-scale carbon sequestration.

Color is white or gray, also tinted yellow or brown.

Luster is vitreous.

Transparency crystals are translucent to transparent only in individual crystals.

Crystal System is trigonal; bar 3 2/m

Crystal Habits are usually massive forms such as lamellar, fiberous and course to fine grained rocks. Crystals are extremely rare, but when found are in the form of rhombohedrons or hexagonal prisms with a pinacoid termination.

Cleavage is perfect in three directions forming rhombohedrons.

Magnesite is used in the manufacture of ESPOM salt, face powder and disinfectant.It is also used as a catalyst, a refractory material, and a filter in the production of synthetic rubber and a material in the preparation of magnesium chemicals and fertilizers.

TALC

Crispin Malvika, group 5. Scientific adviser is Tatyana Tishakova

The FDA has studied talc used in cosmetics for asbestos. Samples were considered safe, but monitoring continues. Talc is used for in a wide variety of applications. In all of these applications, talc is a functional ingredient. Talc is rarely used as filler since it is expensive. Uses for talc include in ceramics (principal use), paper, roofing, paint, plastics, rubber, cosmetics, agriculture and food.

YELLOW CALCITE

Mohanad Qalasi, group 5. Scientific adviser is Tatyana Tishakova

Yellow calcite that stimulates the intellect. It can help one organize intellectual thoughts and information.

Yellow calcite also boosts one's general energy level. From this, it increases one's personal power, hope, and sense of self-worth.

Yellow calcite is also very helpful for psychic abilities and meditation. It assists with channelling, intuitive awareness, shamanic work, and other psychic activities.

In the physical realm, yellow calcite is said to benefit the stomach, upper intestines, upper back and upper spine. Note that healing crystal meanings are spiritual supports to healing and are not prescriptions or healthcare information.

Yellow calcite is associated with the solar plexus chakra.

Also see Calcite for mineral data and additional metaphysical properties and healing properties common to all calcites.

Yellow Calcite is often used to enhance one's will and self-confidence. The sweet, subtle, and vibrant energy of these Yellow Calcite tumbled stones can sometimes be felt when placed directly on the Solar Plexus Chakra, and can infuse one with a sense of new hope and optimism to face the future. Those who can benefit most from Yellow Calcite's work on the Solar Plexus are people who are pessimistic, sarcastic, or overly analytical. People with anger management issues can meditate with Yellow Calcite to help open them up to a knowledge of Divine Love and compassion, which can soothe the fire within that often causes violence.

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