Assam silk denotes the three major types of indigenous wild silks produced in Assam—golden Muga, white Pat and warm Eri silk. The Assam silk industry, now centered in Sualkuchi, is a labor-intensive industry.
Muga silk is the product of the silkworm Antheraea assamensis endemic to Assam. The larvae of these moths feed on som (Machilus bombycina) and sualu (Litsaea polyantha) leaves. The silk produced is known for its glossy fine texture and durability. It was previously reported that muga silk cannot be dyed or bleached due to "low porosity", but this is incorrect; muga takes dye like any other silk. This silk can be hand-washed with its lustre increasing after every wash. Very often the silk outlives its owner.
In 2015, Adarsh Gupta K of Nagaraju's research team at Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India discovered the complete sequence and the protein structure of Muga Silk Fibroin and published it in Nature Scientific Reports 
Eri silk is made by Samia cynthia ricini which feed on leaves of Castor oil plant (Ricinus communis). It is also known as Endi or Errandi silk. Because manufacturing process of Eri allows the pupae to develop into adults and only the open ended cocoons are used for turning into silk, it is also popularly known as non-violent silk. This silk is soft and warm and is popular as shawls and quilts.
History of Assam Silk
Assam was well known for the production of high quality silk since ancient times. The craft of weaving goes along with the production of silk. Weaving is an important characteristic of North East India Neolithic culture. It had been practiced among all the ethnic groups of Assam. The craft of weaving grew to such sophistication in Assam that it was known all over India and abroad. Kautilya’s Arthashastra, a political literature of the 3rd century BC, makes references to the highly sophisticated silk clothing from Assam. The knowledge of sericulture probably arrived with the Tibeto-Burman groups who migrated from China around the period of 3000-2000 BC. Moreover, there was another trade of Silk through the Southwestern Silk road which started from China, passed through Burma and Assam, finally getting connected to the main silk road in Turkministan.
There are various other records to show that Silk came to India through Assam. There are references of Assam silk in the records written by Huen Sang where he has written the use and trade of Silk in Kamrupa during the rule of king Bhaskar Varman. Ram Mohan Nath in his book "The Background of Assamese culture" states that: "The Kiratas,(an early Mongoloid race in Assam), were traders in silk, a word that was derived from the Mongolian original word ‘sirkek’. The Indian word ‘sari’ is probably derived from the same word. “It is therefore clear that in ancient times traders from different parts of Tibet, Central Asia and China flocked to Assam through various routes, and as they traded mostly in silk, they were generally called Seres – Cirrahadoi – Syrities – Cirata-Kirata. The word Kirata therefore, is a general term referring to the people of the Mongolian origin and it refers specially to the Bodos.” These Bodos referred by Nath are today known as Bodo-Kacharis which includes groups such as Boros, Dimasas, Chutias, Rabhas, Sonowal, Garo, Koch and many more. J.Geoghegan in his book "Silk in India" states that: "It is the Kiratas who introduced the cultivation of silk with its different varieties in Assam and it is from Assam that Silk was later introduced to mainland India. Whatever may be the date of the introduction of the worm, its geographical distribution at present day, and the fact species first introduced was a multivoltine, seem to me to lead to the conclusion that the insect was first introduced into India from the north-east (i.e. Assam)".
Genetic research on silkworms show that Assam Silk originated in two specific regions of Assam. One was Garo Hills in the ancient Kamrupa kingdom and the other was Dhakuakhana in the ancient Chutiya kingdom. Later during the rule of Ahom kings, silk was given royal patronage in the 17th century.
The silk industry of Sualkuchi
Sualkuchi is a multi-caste town under of Kamrup (rural) district of Assam, situated on the North bank of the mighty Brahmaputra at a distance of 30 km West of Guwahati. The town is linked with Guwahati by P.W.D roads and with Palashbari on the South bank by motor boat and country boat. As per 2001 Census, the total population of Sualkuchi was 21252 with 4023 households. The average household size is 5.28 with sex ratio 1045. The literacy rate is 64%. S/C, S/T population constitutes 26% and 2% respectively of total population of Sualkuchi. Sualkuchi is located in the latitude of 26°10'0"N and the longitude of 91°34'0"E. The hottest season of the year in Sualkuchi are May to middle part of September. As mighty river Brahmaputra flows in the South direction of the village, a sort of breezy air flows throughout the year. The village is thickly populated. Approximately there are 2,24,381 peoples (according to 2001 census report) inhabitants in this village. The major occupation of the people in this village is weaving. Most of the areas in this village are plain but in some part of north-eastern and central side in this village are covered by small hills.
As per the Census report of 2001, the workforce participation rate in the town was 37.93% of the total populations, of which only 0.53% were cultivators, 1.2% were agricultural labours, 56.37% were engaged in household industries and the remaining 41.90% were engaged in other activities.
Although Silk was cultivated and woven by women all around Assam, the silk clothes of a particular place named Sualkuchi achieved much fame during the Ahom rule. Silk was given royal patronage during that period and Sualkuchi was made an important centre of Silk weaving. The Hand-loom industry of Sualkuchi encompasses cotton textile, silk textile as well as Khadi cloth which are, in fact, traditional cloth endowing high social and moral value in and outside the state. However, Sualkuchi is well known for silk textiles both mulberry and muga silk. In fact muga, "the golden fibre" is produced only in Assam and it has also tremendous export potentiality. Such activities are intimately linked with the culture and tradition of the Assamese people since long past.
Having a long tradition of silk weaving at least since the 17th century, Sualkuchi is the prime centre of the silk hand-loom industry of Assam. Although originally it was a "craft village" having several cottage industries till the forties of the last century such as hand-loom weaving industry, oil processing in the traditional ghani, goldsmithi, pottery etc., the industries other than hand-loom are now almost extinct and the artisans have already taken up silk weaving as a profession. Although the weaving industry of Sualkuchi remained almost confined within the Tanti Community of Tantipara up-to the 1930, later people belonging to other communities also started to take up silk weaving gradually. Now, even the fishermen of the Koibortapara hamlet of Bamun-Sualkuchi and the Brahmin families have also given up their ascriptive caste occupations to a larger extent and they have taken up silk weaving as the main source of income.
The weaving industry of Sualkuchi received a big boost during the Second World War. The growing demand for fabrics and their increasing prices, encouraged a few Tanti families to introduce weaving commercially and they started weaving factories engaging hired wage weavers. Today, the factory system with semi-automatic Fly shuttle handloom has already been extended to entire Sualkuchi and 73.78% of the households of the town are being engaged with commercial weaving of hand-loom. The Census of Hand-looms in Sualkuchi conducted in 2002 reveals that Sualkuchi has 13752 active commercial hand-looms, of which 54.75% are performed by the woman weavers, who are basically hired from the outside of Sualkuchi. Although the hired wage weavers were originally the local poor from the Bamun-Sualkuchi area of the east and Bhatipara hamlet of the west, a flow of migrated wage weavers from different parts of Assam has emerged gradually since eighties of the last century and presently migrant weavers are dominating the wage weavers of the town.
Even Gandhiji, the father of the nation was also highly surprised about the art and culture of weaving of the Assamese women when he visited an exhibition of eri and khadi clothes in Sualkuchi on the 9th of January, 1946. He was greatly astonished when he saw that one of the expert weavers of the silk town had depicted him in the cloth produced in his hand-loom.
"Khat khat khat khatsalare sabade prean mor nite nachuyai" was one of the most popular radio songs composed and sung during the fifties of the last century by the present artist pensioner Narayan Chandra Das Of Sualkuchhi. Actually the 'click-clack click-clack' sound of the loom make the soul of the passerby dance with the rhythmic rattle of the shuttle flying through the sheds of the wrap. No doubt, there are nearly 12 lakh throw and fly-shuttle handlooms in Assam, but most of them are domestic weaving a few metres of cloth for the use by the family members. There are also some semi commercial looms producing some metres of fabrics for the market during the off hours of the house-wives doing either independently or under some so called "Mahajans" who supply yarn to the poor weavers, who return the woven cloth against wages per piece.
The number of purely commercial looms working throughout the year and producing different verities of fabrics only for the market is not very much encouraging. The silk loom of Sualkuchi and the Cittaranjan looms of Silchar had held a predominant position as per a report of the Textile Enquiry Committee of 1954. Sualkuchi However holds now the unique position in Assam nay in North East India by producing pat (mulberry), muga and tasar fabrics of various designs and colors. It has very expert designers and weavers. On the occasion of the visit of Mahatma Gandhi to Sualkuchi on January 9, 1946 one designer Rajen Deka, designed the picture of Gandhiji got it woven in a piece of pat cloth and was presented to him. The woven picture was so fine that even the two broken front teeth of Gandhiji with a smiling face were depicted and while seeing the picture the father of the nation remarked that the weavers could weave dreams in their cloth.
Sualkuchi an ancient craft village-having silk-rearing and weaving communities, potters, goldsmiths and oil pressures. While silk-rearing vanished long time ago, the gani industry perished during the early the part of the last century as the 'Mudois' of Sualkuchi.