I've been studying a lot of late, in particular doing a bunch of research into gold and silver (as if I can afford much but hey!)   Anyway been learning some interesting things.  I found it really interesting that gold bullion bars are still one of the major items used for large scale financial transactions between nations.  It is as if gold as a currency didn't actually go away, it simply retreated to being used by central banks and governments.  So even though currency is paper, it seems that gold reserves are still a tangible and perhaps essential measure of real wealth.   Fascinating stuff.  Also really interesting was the amount of processing that goes into making gold bars.   Extracting and purifying gold from ore is not simple - there are many stages that need to be undergone in order to make really pure (99.9%+ pure) gold.   Different impurities need to be treated in different ways in order to remove them.   What's interesting is that many of the processes involved in gold purification and assaying are quite ancient and have not changed all that much since old times.   Other aspects of manufacture however are quite new - for example the making of the kinebar - which has a hologram-like image in the surface of the bar as a form of high-tech security.... all good stuf

I found out that different essential oils have different methods of extraction.  Turns out that Jasmine is best extracted using the modern method of "supercritical CO2".   High temperatures affect the delicate aromatic substances that make up the Jasmine scent - and the old method used (enfleurage) is very labour intensive.    Another possible method is solvent extraction - but it has been found that small amounts of the solvents are left behind - meaning that the purity (and "naturalness") of the product is compromised.    With CO2 extraction, all the CO2 evaporates under normal pressure and temperature, leaving the pure product.   Way cool.