One sweater says lambswool, the other says merino. What does that mean? What’s the difference?

This cashmere sweater costs £30; this other one costs £300. Can they really be made of the same thing?

In our first chapter of this series – The Guide to Knitwear – we summarised all the things that made one sweater different to another, from yarn to gauge to loom.

Now we start taking deep dives into each one, beginning with fibre. This is the raw material the knitwear is made of, whether wool (merino, lambswool, geelong) another animal product (cashmere, vicuna, silk) or a plant (cotton, linen, hemp).

By explaining what they are, their different types and their properties, it will hopefully help readers understand what they’re buying and make informed choices.

Plus it’s kind of interesting.



What are the types of wool?

The vast majority of high-end knitwear – the kind Permanent Style readers might be considering – is merino, from a merino sheep (above). This is not a British breed, but usually imported from the likes of Australia and South Africa.

So if a label says something is merino, it’s not telling you much. It’s just ruling out other breeds – usually coarser and British, of which the best known is shetland – and probably telling you it’s adult merino, not lambswool.

If it is lambswool, the label will usually say so, and it means the wool comes from the first shearing of a sheep. Which makes it finer and softer.

(Interestingly, the way you identify lambswool is by looking at the fibre under a microscope and seeing that it has one pointed end and one square. The squared end is where it was cut, the other end is the tip. All future wool taken from the sheep will have a cut tip, so both ends are square.)

Once you know it’s merino lambswool, you’re into specialty breeds or flocks.

For example ‘geelong’ refers to a particular type of merino sheep, which originally came from the geelong area of Australia. It was particularly high quality, and so sought after.

In recent years, geelong wool has increasingly been processed in China, rather than Australia, which makes it a less reliable indicator of quality. But geelong will still usually be a particular fine merino. (Though not, in my experience, as nice as cashmere, despite being marketed as such.)



Why does this matter?

So, we have there a series of subsets. Geelong is a type of lambswool (above), which is a type of merino, which is a breed of sheep. 

What do we get as we descend that structure, using ‘better’ wools?

The biggest factor is fineness, which is measured in microns. Adult merino might be up to 21.5 micron, lambswool anything from 16.5 to 20, and geelong 18.5 or so. A human hair averages 70-80 micron, by the way, so this is all pretty fine.

There are other attributes of the wool fibre though. One is softness. Although fineness largely determines softness, lambswool of the same micron as adult merino will still be softer. And cashmere is softer because it has fewer scales in the fibre structure.

Another is length: one issue with cashmere is that although it’s fine and soft, it’s shorter than most merino. And another is colour: pale, almost white wool is prized because it can be dyed into a greater range of colours.

Then there are some peculiarities of different specialty wools, such as the crimped shape of Escorial wool, which is another merino breed.

When these fibres are spun into yarn, you get a whole set of new differences, which we might cover later. But the biggest one is worsted and woollen-spun. Just as with woven materials in suits, a worsted yarn is spun finer to create a smoother, often denser product. It’s what you see in light knits, such as those of John Smedley. Other, normal jumpers are woollen spun.

This only matters here because a coarser fibre can still look and feel fine if it is worsted.



The types of cashmere

Cashmere’s added value is fineness. Chinese cashmere (above) will be around 15 to 16 micron; Mongolian is 16.2 up to 18; Afghan is coarser and generally used for weaving. But all are finer than lambswool.

(There’s also baby cashmere, which is the first combing of a cashmere goat and is the finest of all. But, according to those I spoke to, there is far more ‘baby’ cashmere in the world than could realistically come from these animals.)

There is some real variety there among types of cashmere, which explains a lot of the price difference. There’s also variation in length of the fibres and mixes of length.

But just as important how the cashmere is used.

A lot of cheap cashmere, for example, is knitted loosely so less is required. A chemical softener is used to make it feel softer (and give it a slightly oily touch) and it’s over finished, making it very fluffy but not as strong. More on that in an article here.

There is also some traditional difference in how cashmere is knitted. For example, Scottish knitwear usually has less of a finish (less fluffy) than Italian. With the former you can usually see the yarn more clearly.

We talked about the advantages and disadvantages of that in this previous article. But the important thing to remember is that denser Scottish knitwear softens with wear and washing, and should last longer. Judging knitwear just based on what you feel in a shop is rarely that accurate.

Among other luxury fibres, vicuna is finer still, though shorter than cashmere. It’s an amazing fibre, but often hard to justify given how very expensive it is.

There’s also camel, which is around 16 micron, and mostly limited by its colour. And a little alpaca and angora. The latter is a very short fibre, and produces a particularly fluffy texture.



Plant fibres

Fibres like cotton and linen are mainly used for Spring/Summer, to make knits feel cooler. Both are cool to the touch, and trap heat less.

Cotton is seen more often because not everyone likes the crispness of linen, even though cotton is heavier and not quite as cool. Hemp behaves in a similar way to linen.

Sometimes the best solution is to mix cotton or linen with wool or cashmere. This produces more of a mid-weight jumper, not as cool as the two plant fibres on their own, but still lighter and fresher than wool.

The mixing can actually be done in two ways – one where the fibres themselves are mixed together before being spun, and another where one spun yarn of each is twisted together. The advantage of the latter is that the proportions are easier to control.

Silk is fantastic for strength and lightness, but again has a disadvantage in producing a sheen on the surface. So it’s most often used in mixes, usually with cashmere in lightweight knits.

There are differences in the qualities of all of these fibres, with Egyptian or Supima cotton having a longer staple length for example. But the differences are not as marked as those between different wools and cashmere.

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Hi Simon,
A very informative article. Thank you.


Another wonderful article, Simon. Thank you. Are mills as major a factor for knitwear as they are for suiting? I haven’t really heard people discuss mills for knitwear, but perhaps I’m uninitiated on that point.


Useful post, thanks Simon. Recently I bought a couple of yak and yak-wool pieces of knitwear. I like them, though the 100% yak cardigan is a little scratchy/glassy, almost like mohair. Maybe worth covering as well?


“There are differences in the qualities of all of these fibres, with Egyptian or Supima cotton having a longer staple length for example.”
It might be worth pointing out that Supima (strictly, SUPIMA®) is not a type of cotton but a brand for a type of cotton called Pima, which is grown exclusively in the US.

Peter O

Thanks for that distinction between Brand Supima and genus Pima! Simon’s article also has valuable details new to me for which I’m grateful!

Ivo Zuazo

Indeed, although Pima is grown in Peru as well and originally from this country.


Hi Simon, great article as always. From my experience knitwear makers in europe don’t offer many products with fibers like vicuna or alpaca or camel. Maybe it’s a more regional thing. I actually acquired an alpaca sweater, hand knitted, recently from a maker in Peru and it is super soft. Do you thing having knitwear made of any of this fibers is worth it if you are just starting getting knitwear? Or would it be something that you would only get when you have a solid collection of knitwear with more common fibers (cashmere, lambswool, merino, etc)?

Thank you.


What’s the best way, besides brand, to tell the durability of a wool jumper? Here you say that its hand in store isn’t a great indicator. It all seems a bit mysterious to me.


Hi Simon. Could you please expand on what you mean with a refresh from a specialist? I had read from a reputable Scottish knitwear producer that I should postpone washing until strictly necessary and instead use “air washing”, thus refresh it outside from time to time. Any thoughts?


Excellent video and great, thorough questions. I learn a lot from the video. Thank you.


Thanks, Simon, good article as always. I’ve always avoided cotton ‘knitwear’ as I find that (1) it loses its colour, as cotton does, and (2) it loses its ‘spring’ and therefore its shape – eventually feeling a bit stiff and lifeless and getting too baggy. Wool and cashmere of course can still look wonderful years after you first bought them. It would be nice though if there was something you could get in a lighter fabric that didn’t suffer these problems.

Oh, and on the subject of silk/cashmere blends, I still wear a RLPL silk/cashmere sweater that I must have bought at least 15 years ago. It still has all of its elasticity and has only faded slightly, and it is absurdly warm for such a lightweight piece.

Thomas Mastronardi

Much more than simply “kind of…”


Hi Simon – superb blog. Just wanted to clarify, merino sheep (ovejas merinas) are originally from Spain.



The article reads (on merino): “This is not a British breed, but usually imported from the likes of Australia and South Africa.”

Well, it is as a matter of fact a Spanish breed. Also an interesting piece of historical knowledge.


Re wool, if it isn’t from a certain breed such as merino and it’s from an adult is this when it’s referred to simply as virgin wool or new wool? I’m surprised I don’t even see jumpers on the cheaper end use it – is that used for suits and rugs etc?


very informative. I always associated a ‘merino wool’ label with finer, smarter knits; and a ‘lambswool’ label with spongy, scratchier knits…almost shetland like. i think it was probably because Uniqlo sells them that way, which is confusing.

Have you had any experience with Alpaca knits?


What about Shetland and other British wools? How thick are there? How durable are there and so on ? I think it might be useful to include those details because Shetland sweaters (and other similar types?) are often mentioned here on PS.


Do you have any recommendations for Shetland sweaters online, Simon? I am finding them hard to source. I recall you have sometime endorsed Dicks of Edinburgh but they currently offer surprisingly narrow colourways. I am looking for something along Ivy lines.



Hi Nico, I’ve bought a couple of Shetlands from Dicks in the last 12 months. It’s worth keeping an eye on their website because when they restock they have a great range.

Astrid Andersson

Can’t see past Bosie for wool sweaters, the quality is astounding for the price.


Really quite fascinating; yet still a bit of a minefield. Its lovely to learn more about all of this – thank you.

It always makes me smile when talking with those less informed (not making a judgement, just that some don’t know/haven’t looked) that there is a belief there is just one type of each, i.e. ‘a’ cashmere jumper, ‘a’ wool jumper, etc.

Thanks again – informative, interesting, stimulating; and not condescending.

Ondřej Ručka

Hi, Simon. How would you rate cashmere sweaters from JOHNSTONS OF ELGIN and Eric Bompard? Thanks!

Ian Skelly

Has anyone used love cashmere for alterations ? I have a really nice n peal cashmere cable knit but the length and sleeves are too long

Ian skelly

Excellent I will drop them an email to see if they are back up and running , thanks


I have a silk and cashmere blend sweater that I bought in Italy. It has been excellent – fine, durable and non-pilling. They seem hard to come by though. Does anyone know where to find them?


The Luca Faloni sweaters seem to be a very close fitting slim fit. Does anyone know of a brand(s) which offer a more relaxed, regular fit in this blend of materials? Thanks.


My experience with Luca Faloni sweaters is that whilst they are quite slim fitting, they tend to “relax” a little with the first few wears. I’ve found that to be the case with other brands too.

Peter Hall

Ian. The German company Fynch-Hatton occasionally use it in their sweaters.
Not the highest of PS quality, by any means, but sweaters are certainly roomy. Quality is decent, nothing more, (I have a couple of their cotton jumpers which I use for layering).


Great article! I hope that you in a future article could cover how different materials impact the environment and what to avoid if you want the animals to be treated well.


Cashmere’s ability to pill into bobbles on the surface is extremely annoying and worth mentioning as more care needs to be taken with the clothing.

Think I’ll try Merino or Alpaca next.


Informative and interesting.


Great article. The merino knits I own start to itch after a couple of hours even though they are marketed that you could wear the right on your body. – Am I oversensitive or is it a sign the the wool has low quality? If so, any tips on how to find that out before I buy it? Its hard to tell by just trying it out in the store.


After some further investigation I have come to the conclusion that some merino wool sweaters that I own is of lower quality (or coarser if you will). So it’s not me, it’s the sweaters. Which is good news.


Hi Simon,

Very interesting. I wondered if you have any guidance on fabric pairings (for example, with worsted wool pants wearing merino rather than lambswool etc).



Thanks for getting back to me – I think a separate article would be great, would be very interested to hear your thoughts on the different variables! Cheers

Nicolas Strömbäck

Summer wool is a term I have seen more and more. Does this refer to a particular blend or is it just thinner and coarser wool?


Happy New Year Simon – thank you for this article from a new reader. You mentioned that Vicuna fibre is shorter than cashmere; would you have a source for this? What has been your experience with vicuna knitwear? Thank you.


Many thanks for your reply. Wishing you health and success in 2022. Best and warmly.

Peter O



I asked Johnstons of Elgin for their cashmere fibre lengths and diameters but received no reply, so I’m not sure how easy it is in practice to get those values.


Update – I did eventually get a reply only to be told that the company ‘would not normally divulge that level of information’. I haven’t asked any other brands, but trying to assess knitwear quality using fibre dimensions may be a waste of time.


Very interesting article. I actually stopped buying cashmere because of its delicacy, the environmental problems it causes (desertification in Mongolia) and the dubious treatment of animals in the countries where it is produced (mainly Mongolia and China).
For the same reason, I prefer Merino from New Zealand (e.g. John Smedley) or Switzerland where the animal protection standards are much higher than in Australia.


Hello Simon. Given your fondness for RL, what is your view on the relative value of the Purple Label cashmere jumpers? My assumption is it’s highest quality cashmere of Italian make, so not as robust as Scottish cashmere would be. Thanks!


Morning Simon,

I’m considering a quality cotton sweater. How well will such a thing (hand)wash? Will it need even more care than wool to preserve the shape?

And all else being equal, would you suggest washing cotton slightly more often than wool? I know wool is famed for its antibacterial qualities.



Thank you, Simon. Does it hold its shape as well as wool over time?


Hi Simon,
I live in a warm/humid climate (Florida). I do like to visit colder climates, if only to enjoy wardrobe variation 🙂 So my question is regarding summer knitwear, as it is what most would consider “summer” for 75% of the year, here.

Would you recommend sticking with fine merino from Smedley even your own PS Shop in an effort to keep the temperature down? I would always wear over a collared shirt (but, due to heat, often a poplin with a button dollar instead of true oxford, as they are so thick).

I have liked some of the knit t shirts Anthology have put out for summer, or the Bryceland Cotton Short Sleeve Skipper polos, but haven’t tried in the heat.

Are the silk/cashmere blends a better idea, say like the Colhays tennis polos?

Thank you in advance for your advice!


This is incredibly helpful, thank you!

If I am understanding, you’re saying fine knits aren’t worn over shirts, or not over something stiff like oxford cloth? So a smooth/light poplin would work? That’s my usual go-to.


Ah I see, thank you.

On that note, do you know if the Finest Crewneck will be restocked, this year?


I can wait until Autumn 🙂
Thank you, again!

Hewad Amiri

Hi Simon,

I am trying to find Scottish Cashmere yarn to buy so my mom can make me a sweater. Unfortunately I was not able to find anything online that would supply quality Scottish cashmere. Would you be able to guide me towards a shop?
Thank you and best regards