The plant Indigofera Tinctoria grows in abundance in Southeast Asia and the Indian subcontinent, it is a different species from Persicaria tinctoria or Japanese or Chinese Indigo which grows in East Asia and Eastern Europe. For centuries the indigo plant has been used to create the most brilliant natural blue dye that was traded, like money. It can be said that dye even predated our modern currency whether as indigo dye bricks or as indigo fabric lengths.
This "Blue gold" played a part in the Californian gold rush, the indigo denim (De Nimes as in originating in Nimes, France) jeans Levi's Strauss became the uniform of gold rush. In East Africa, synonymous with the nomadic Tuaregs or the blue men of the Sahara. In Southeast Asia, indigo is synonymous rice farmers, whom are backbone of these agricultural countries. In Thailand, in the province of Sakon Nakhon in the Isan region, in the Northeast of the country, Indigfofera Tinctoria grows in abundance with Sakon Nakhon Indigo recognised as a Geographical Indication.
The leaves and stalks of the Indigofera Tinctoria plant goes through a process that transforms it from a plant to a living, breathing natural blue dye.