Vanadium as a colouring element is quite often underestimated, mostly as it is often associated and acting together with chromium, a chemical element with a similar geochemical behavior and parageneti

Paraiba tourmalines owe their attractive colour to the presence of copper. In the best case, this gives rise to a vivid blue colour, also known in the trade as ‘neon’ blue or ‘electric’ blue a

Recently, a beautiful Vietnamese ruby of 2.10 ct and vivid red colour was submitted to SSEF for testing. Microscopic observations and chemical trace element analysis confirmed its Vietnamese origin an