A Rockcloud silk filled duvet is exquisitely handmade by skilled craftsmen. The silk from the cocoons is stretched out into layers and laid in a criss-cross pattern. This method retains the most stability and thermal benefits. We do not box stitch our silk duvets as this results in unwanted cold spots. This finest Grade A silk floss adheres itself naturally in place. We have designed each silk duvet with a side opening to allow inspection of the high quality 100% long mulberry silk floss inside and the silk is wrapped in a white pure cotton cover which is beautifully made with piped edges and white embroidered logo. Rockcloud silk is the result of the tireless work of the Bombyx mori silk worm. They feed on mulberry leaves, which produces the finest strongest silk in the world. The Bombyx mori construct oval-shaped cocoons, each producing over 1000 metres of silk. This is spun in a continuous filament and can reach a single length of up to 1800 metres which is the longest natural fibre. Silk is extraordinarily strong and resilient. Rockcloud silk is pearl white and can reflect natural light. The silk thread is long and well aligned. An inferior silk can look dull or pale white. Rockcloud silk has no hard areas and feels very soft and smooth. An inferior silk feels rough and uneven and is mixed with fragments of damaged cocoons and broken waste filaments. Silk floss is self extinguishing. Rockcloud silk is very flexible and has good elastic recovery. Cheaper duvets frequently use short silk floss or wild silk floss, alone or in combination with mulberry silk. Short Silk floss is non adhesive and feels like cotton and, when used in a duvet, requires machine stitching to keep the silk in place, which produces unwanted cold spots. Wild silk is naturally grey in colour, thick, short and not as soft or elegant as our mulberry silk. This type of silk tends to adhere to each other in a cube shape, so it is not easy to arrange in an ideal structure for a duvet.