Chromium

Photo Credit: Periodictable.com

Atomic Number: 24
Relative Atomic Mass: 51.99
Group: 6
Period: 4
Block: D

Symbol: Cr

Chromium is a hard, silvery metal which has a blue tinge. The metal is usually found in chromite - a mineral which is the only ore for Chromium. Chromite is actually an iron chromium oxide (FeCr₂O₄) and 99% of it is found is in southern Africa (according to the Mineral Education Coalition). Although, the Royal Society of Chemistry state that chromium ore can be also be found in many other countries such as South America, Turkey, India and Kazakstan.
You can even reduce Chromium (III) Oxide (Cr₂O₃) with either Aliminum or Silican to form Chromium. Normally, Chromium made by reducing the ore with Carbon in an electric-arc furnace.
As you can see from the photo (beneath), an electric-arc furnace are giant industrial sized circular vessel which sits on rollers that allow the metal to tip.

An Electic Arc Furnace
Photo Credit: Wikipedia

Discovery of Chromium

Photo Credit: Britannica

Chromium was discovered in the year 1798 by the French chemist, Professor Nicolas-Louis Vauquelin. Professor Vauquelin didn't just discover Chromium. A year earlier, the professor discovered another element of the periodic table - Beryllium (Atomic Number: 3). Chromium was only discovered though because the professor was intrigued by a bright red mineral which had been found within a gold mine in Siberia in the year 1766. The new material was known then as Siberian red lead, now Crocoite... And chemically, the material can be called Lead chromite (PbCrO₄). But, I'll leave it to you to use the name that you like.
The chemist analysed the crocoite and comfirmed that the mineral was a lead based material. He dissolved the lead chromite in acid then allowed the lead to precipate (form a solid) from the solution before filtering the lead out. Vauquelin focused his attention on the liquid which remained. Though by doing that, he had successfully isolated Chromium.

This is Crocoite.

Photo Credit: Wikipedia

Professor Vauquelin was fascinated by the large range of colours that Chromium produces when the metal is in solution form. It is why Chromium is named Chromium... The word 'chromium' comes from the greek word Chroma which means colour.

Plus, the professor also discovered that the green colour within emeralds was due to the chromium in the gem.

Biological Uses

Chromium does indeed have a biological used. It is used in trace amounts in humans, helping us to take in glucose. However, chromium in excess is poisonous. In an average day, we take in 1mg daily. Chromium can be found in food products such as yeast, wheat germ and kidney.

It's Uses

• Many shiny things in the home are Chromium plated
• A really thin layer of Chromium is plate on top of a cheaper metal - normally steel
• Chromium is used to harden steel 
• Manufacturing stainless steel - Named soon as this steel doesn't rust
• Chromium plating can be used to give a polished finish to steel
• Chromium-plated car and lorry parts such as bumpers were very common at one time
• Chromium-plated plastic are often used in bathroom fittings
• About 90% of leather are tanned using chrome (Chromium)
• Though the waste is very toxic 
• Chromium compounds are used as industrial catalysts and pigments (bright green, yellow, red and orange). 
• Rubies are red due to Chromium
• Glass treated by chromium turns emerald colour