30 BC – 476 AD
Because there was so much trade across the empire, the Romans could get the brightest and best minerals to colour all the things they wanted to paint.
Just look at this bright red colour below! That’s cinnabar from Morocco.
Minerals are naturally occurring substances – that means they’re not manufactured.
They are also substances that have never been alive. Rocks are made up of a combination of minerals and non-minerals. But if minerals are locked up in rocks, how do you turn a load of rocks into paint?
Well, you would grind up rocks into a powder, which you would then mix into a solution so that the really colourful parts could be separated from the other stuff.
The Romans were making use of the way chemicals work together, even if they didn’t realise it!
The pigment – that’s the colourful part – would have been mixed with a binder like egg to make it sticky enough to use. They would try and make as much paint as possible as these minerals were often super rare which meant they were also super expensive!
Glass is another cool way the Romans used chemistry.
To make glass, you need a former – that’s the stuff whose molecules give glass its rigid structure – like sand.
Sand is just ground up bits of shell and rock. How good the sand is as a former depends on what type of rocks have gone into making it. Luckily, the Romans used sand that contained a lot of quartz and lime, which worked really well.
Another mineral called natron has to be added to the mix – it’s just like making a cake, with each ingredient having its own specific job. Natron helps make the sand melt more easily by lowering its melting point.
The final ingredient for glass is a fixer to help make it tough! Lime was often used, which stops the glass from dissolving if it gets wet. The cool thing is that this technique is still used today!
By adding different chemicals into this mix you can create different coloured glass!
By adding tiny particles of gold and silver, the glass will even change colour when light is shone through it!
Romans loved making things fun as well as useful. The amazing thing is that the colour changing effect only works when the particles of gold and silver are super tiny. The picture above is the famous Lycurgus Cup in the British Museum – just look at the effect produced by the light!
You might have heard of the famous Roman city of Pompeii.
Pompeii was an Italian city destroyed in 79AD after the eruption of Mount Vesuvius! The city was covered in many metres of ash and pumice – that’s rock from the volcano.
However, in museums today you can find Roman pottery, glass and frescoes – a type of painting on wet plaster – from Pompeii. How is this possible?
Well, this covering of ash and pumice actually preserved what was underneath, and did it so well that many of the objects – and even houses and streets buried – look almost as good as new!
The trouble is that once they are taken out of the ash, these delicate artefacts can start to crumble. Things like moisture in the air, strong light and bacteria all cause damage. That’s meant that despite surviving for almost two thousand years, some of them have finally been lost for good.
Want to explore some more? We’re fast-forwarding to the Rennaisance period next!