Opal:
Opal has been a mystery for centuries. No two opals look alike. The word ‘opal’ was derived from a Greek word opallos, meaning “to see changes of color”. Opal is derived as a precious gemstone which is formed from non-crystalline silica gel. It consists of 6 to 10 per cent water and small silica spheres [...]

Large lumps of copper are found in the ground in the form of nuggets.  Copper, which has an important commercial use as an electrical conductor, heat conductor and building material, has been used by humans for various purposes for thousands of years.  In recent years, Chile has been the top producer of copper followed by [...]

Zinc can be found in many places including the air, soil, water and in the food we eat.  It is found most abundantly in the crust of the earth.  Zinc is important as we need zinc in our diets.  The shiny, blue/white metal also has many commercial and industrial uses such as being mixed with other [...]

Uranium was first discovered in silver mines in what is now the Czech Republic by a German chemist named Martin Klaproth.   Uranium, a dense silver-white metal, is found abundantly in the crust of the earth.  It’s also found in soil, rivers, the ocean, in the food we eat and even – in trace amounts - in human [...]