What 6A grade silk actually means

If you have shopped for silk you have seen the claim: 6A grade mulberry silk. It sounds like a certification, and it is a real classification — but it measures something narrower than most listings imply. Here is what the grade actually covers, and where it stops.

Skeins of raw reeled mulberry silk yarn with cocoons
Grading happens here: reeled raw silk, before it becomes cloth.

What the grade is

Silk grading comes from the Chinese national standard for raw silk (GB/T 1797). Raw silk is classified on a scale running from 6A at the top down through 5A, 4A, 3A, 2A and A to B, C and below. 6A is the highest band in common commercial use.

What it measures

Grading is done on reeled raw silk and looks at how well the filament came off the cocoon. The tested properties include:

  • filament length and how much of it is unbroken
  • size deviation — how consistent the thickness is along the strand
  • evenness across the batch
  • cleanness and neatness — the count of slubs, neps and loose ends
  • tensile strength and elongation

In plain terms: a batch that reels into long, even, clean filament grades high. A batch with frequent breaks, thickness variation or visible defects grades lower. Higher grades are a minority of total production, which is why they carry a premium.

The part most listings leave out

Grades apply to raw silk — the yarn stage, before it is thrown, degummed, woven, dyed and made up. A finished pillowcase or scarf is not itself graded. When a listing says 6A, the honest reading is a claim about the input yarn, not a certificate attached to the item in your hands.

That matters because everything after reeling can still go wrong or go well. Weave, dye fixation, hem construction and seam quality are not covered by the grade at all, and they are what you actually experience. A 6A yarn made up badly will disappoint; a 5A yarn made up well may not.

Grade is not weight

Grade and momme answer different questions and neither substitutes for the other. Grade describes the quality of the filament. Momme describes how heavy the finished fabric is over a standard area. A 16 momme fabric can be woven from 6A silk, and so can a 30 momme fabric.

Weight is usually the more practical variable when you are choosing between two products, because you can feel it. Our range runs 16, 19, 22 and 30 momme; the silk momme guide explains which weight suits which use.

How to read a silk listing

  • Look for an explicit fibre statement — "100% mulberry silk" — rather than "silk-like", "satin" or "silky". Satin is a weave, not a fibre, and can be woven from polyester.
  • Check that the momme is stated. A listing that gives no weight is withholding the most useful number.
  • Treat a grade claim as information about the yarn, not a guarantee about the finished item.
  • Read the construction: closure type, seam and hem finish, and whether a print is carried on both faces.

SuuSilk's range is described as 100% mulberry silk, with selected listings stating 6A explicitly. Where a weight is relevant it is in the product title, not buried in the description.

For how raw silk gets made in the first place, see how mulberry silk is made.

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