Why is gold so valuable?

Gold, like no other metal, has a fascinating history and a special place in the world. For thousands of years it has been used as an ornament of kings, a currency and standard for global currencies, in competitions as symbol of victory and more recently, in a wide range of electronic devices and medical applications. Ancient civilizations used gold for the decoration of tombs and temples. In modern days FMI and WB suggested the use of gold as monetary reference, i.e., the value of a bill guarantees a given amount of gold. In sports the winner gets a gold medal. Other example of gold as symbol of power, health and prosperity is the gold mirror fish Mercedes Benz C63 AMG (Image 1). Although there are doubts whether the car is simple paint or real gold paint, it already arose many debates about expending big amount of money on the beautification of such car.

Image 1. gold mirror fish Mercedes Benz
Source: Autoblog

Why is gold so valuable? 

First, it is important to remember some basic concepts about gold. Gold is a dense, soft, shiny, malleable, and ductile metal. It is a chemical element with the symbol Au and atomic number 79. Its symbol is Au. The melting point of gold is 1,948°F (1,064°C) and its Boiling point is 5,173°F (2,856°C). The atomic mass of gold is 196.96657 ± 0.00004 u. The density of gold is 19.30 g cm-3. Some possible reasons for its high value are its unique aesthetic and special properties.

Color and aesthetic
The symbol of gold is Au, from the greek word aurum, which means glow of sunshine. The english word gold comes from the words gulb and ghel referring also to the color. It is the only metal of this color. The gold's characteristic yellow color is due to the arrangement of its electrons. When alloyed with other metals like silver and cuper it has different colors, according to the percentages of the alloy (Image 2).

Image 2. Colors of gold-silver-cuper alloy
Source: ilcomprooro

Physical and chemical properties
Use Gold has unique physical chemical characteristics that made it very valuable. Gold is the most maleable and ductile of all the metals. One ounce of gold can be drawn into more than 80 Km of thin gold wire. One ounce of gold can be beaten into a sheet covering 9 square meters and 0.000018 cm thick. Gold has an electrical resistivity of 0.022 micro-ohm and a thermal conductivity of 310 W m-1. Hence, it is very efficient for the transmission of heat and electricity. Gold has the highest corrosion resistance of all the metals and it is corroded only by a mixture of nitric and hydrocloric acid. Gold is a noble metal because it does not oxidize.

Scarcity  
The mentioned characteristics are enough to make a very useful and desired metal; thus, a very valuable one. Besides, it is important to consider that gold is rather scarce. It is estimated that the whole gold of the planet equals a total of 168,180 tonnes or 5,407,112,558 ounces. To visualize this volume, let's imagine a single solid gold cube with edges of about 19 meters. This is about three meters shorter than the length of a tennis court.

References and Further Reading

New One World Trade Center

On May 10 2013, the spire of the new "One World Trade Center" (OWTC) was installed in New York. The new OWTC has total high of 1776 feet (541 m), which makes it the tallest building in the western hemisphere, and the third tallest building in the world, after the Burj Khalifa and the Shanghai Tower. The total height of 1776 feet is not random, but was selected as a symbolic reference to America's independence. Live cameras allow to follow the construction progress the 24 hours. The present post will introduce some technological innovations about OWTC, which later will be described with more detail.
Image 1. Spire installation of OWTC
Source: inhabitat

Visual
The OWTC is visible from over 20 miles away. The tower rises from a 185-foot (56 m) windowless concrete base, designed to protect it against truck bombs and other ground-level terror threats. From the 20th floor upwards, the square edges of the tower's cubic base are chamfered back, transforming the building into eight isosceles triangles. Visually, the most striking feature of the interior is, without question, the cavernous lobby. Thanks to the boxlike structure of the podium, there is a soaring 60-foot ceiling?think of Radio City Music Hall’s theater, bathed in light.
Image 2. Panoramic view of new OWTC

Safety
OWTC is one of the safest, technologically advanced, and environmentally sensitive buildings in the world. It has a concrete core, with very thick concrete walls. The three-foot concrete slabs are designed to withstand high winds and earthquakes. The podium has some hefty blast-resistant walls at the base, which are state-of-the-art fire-suppression systems. There are 70 specially protected elevators and a separate, dedicated stairway for fire and safety personnel. According to architect Del Valle, "it may not be the tallest building in the world, but it is certainly the safest”.

Green building
OWTC incorporates not only new architectural and safety standards, but new environmental standards as well, setting a new level of social responsibility in urban design. According to the New York Port Authority, the OWTC has already been certified to LEED Gold and will set the global standard for sustainability. Once the building is fully operation, it’s expected to draw as much as 70 percent of its power from green energy. Some other green facts are:

Fuel cells, waste steam recycling, harvest rainwater, landscaping with more than 400 trees, waste material recycling,  use of green cement, renewable wind and hydro power energy, indoor air quality, daylighting, low water bathrooms, green port a potties

References and Further Reading
A look at the new one world trade center
One world trade center spire installed in New York city
One world trade center
One world trade center live cams
Green facts about New York's new one world trade center