How to Tell if Cashmere Is Good Quality (5 Tests)
Short answer: Cashmere quality is set by fiber diameter and length, not by the "100% cashmere" label. The finest, longest fibers make knitwear that stays soft and resists pilling for years; short, coarse fibers pill and shed heavily after a handful of wears even when the label still legally reads 100% cashmere. You can judge the grade from a listing before you buy by checking softness versus fuzz, ply and density, the care label, how much the surface hazes with loose fiber, and how fast the knit springs back when stretched.
Most vintage cashmere on resale apps is not the luxury heirloom the word implies. A lot of it is low-grade fiber that was never built to last a second season, sold at luxury-adjacent prices to buyers who cannot tell the difference from a thumbnail. Once you can, a $30 Pringle of Scotland sweater and a pilled department-store cardigan stop looking like the same purchase.
It's the Fiber, Not the Label
"100% cashmere" only tells you what animal the fiber came from, not how good that fiber is. Quality comes down to two measurements: how fine each fiber is (its diameter, in microns) and how long it is (its staple length). Finer fiber feels softer; longer fiber stays anchored in the yarn instead of working loose and pilling. The best cashmere is both fine and long, which is why it feels buttery and still looks clean after years of wear.
The informal industry grades you will hear (Grade A, B, and C) roughly track this. Grade A is the finest and longest fiber, Grade C the coarsest and shortest, with the premium end of the market generally aiming for fibers in the mid-teens of microns. Treat those grades as a useful shorthand rather than a strictly regulated standard, because there is no single enforced grading body policing the word "cashmere" on a label. That gap is exactly why two sweaters can share the same label and wear nothing alike.
The 5 Tests for Cashmere Quality
You can run the first two from good photos and a careful read of the listing; the rest you confirm in hand once it arrives.
Tick each test as you assess the sweater
Why Some Vintage Cashmere Gets Softer and Some Turns to Felt
Good cashmere, made from long fine fiber, tends to bloom with age and gentle washing: the fibers relax and the hand softens. Low-grade cashmere does the opposite. Short coarse fiber, especially after decades of hot washing or machine drying, mats and felts into a dense, scratchy board that no amount of care will bring back. This is why era alone tells you little. A 1990s Scottish-milled two-ply crewneck can feel better today than the day it was made, while a cheap 2000s cardigan can already be a felted loss. Judge the fiber in front of you, not the decade on the tag. For the bigger picture on how material drives resale value, see understanding fabric composition in vintage clothing.
What Good Cashmere Is Actually Worth
Here is where knowing the grade pays off directly. A pilled, single-ply mystery-brand sweater and a clean two-ply Pringle of Scotland piece can be listed within a few dollars of each other on the same app, because most sellers price cashmere by the word on the label, not the quality of the fiber. That mispricing runs both directions: real luxury cashmere gets dumped cheap by sellers who do not recognize it, and low-grade cashmere gets marked up by sellers who assume the word does the work.
When you spot a piece worth buying, Crawli compares that cashmere sweater across nine resale marketplaces at once, so you can see whether a $30 Pringle listing is the deal of the year or just the going rate for a pilled cardigan. On a fiber this easy to misprice, checking the cross-platform range before you buy is the difference between a steal and an overpay.