2906, 2014
  • The Chemistry of Gemstone Colours 2016

What Causes the Colour of Gemstones?

June 29th, 2014|

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There are a wide range of gemstones used in jewellery, with each having its own characteristic colour – or, in some cases, a range of colours. The origin of these colours has a chemical basis, and the precise colour┬ácan vary depending on the chemical composition of the gemstone. Interestingly, many minerals are actually colourless in their pure form, and it is the inclusion of impurities in their structure which leads to their colouration.


2103, 2014
  • Inorganic Paint Pigment Compounds

Inorganic Pigment Compounds – The Chemistry of Paint

March 21st, 2014|

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The latest in the Colourful Chemistry series looks at the inorganic compounds that give many paints their colours. This shows a limited selection of the most common compounds, and there are many others; there are also a large range of organic based pigments, which aren’t discussed here (although could possibly be the topic for a future graphic).


1903, 2014
  • Metal Ion Precipitates NH3 NaOH

Testing for Cations – Sodium Hydroxide & Ammonia Precipitates

March 19th, 2014|

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A previous post looked at the colours of transition metals, and the origin of their colours – this graphic, on the other hand, looks at how transition metals (and some non-transition metals) can be identified by the precipitates they form with sodium hydroxide and ammonia solutions. I’m going to keep the explanation of the reasons for the colour changes and precipitates fairly simple here, but I’ve provided links at the bottom of the page if you want to read about them in more detail. […]

503, 2014
  • Transition Metal Ion Colours Aqueous Complexes

Colours of Transition Metal Ions in Aqueous Solution

March 5th, 2014|

This graphic looks at the colours of transition metal ions when they are in aqueous solution (in water), and also looks at the reason why we see coloured compounds and complexes for transition metals. This helps explain, for example, why rust (iron oxide) is an orange colour, and why the Statue of Liberty, made of copper, is no longer the shiny, metallic orange of copper, but a pale green colour given by the compound copper carbonate.


602, 2014

Metal Ion Flame Test Colours Chart

February 6th, 2014|

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This graphic looks at the colour of various metal and metalloid ions that occur during flame tests. Most people probably remember doing this experiment in school chemistry lessons, if not with the full range of ions shown here, but for the uninitiated a brief explanation of the origin of the colours follows.


3012, 2013
  • Chemistry of Fireworks POSTER

The Chemistry of Fireworks

December 30th, 2013|

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The colours in fireworks stem from a wide variety of metal compounds – particularly metal salts. ‘Salt’ as a word conjures up images of the normal table salt you probably use every day; whilst this is one type of salt (sodium chloride), in chemistry ‘salt’ refers to any compound that┬ácontains metal and non-metal atoms ionically bonded together. So, how do these compounds give the huge range of colours, and what else is needed to produce fireworks?