The reason given by Wikipedia for silk fibres being lustrous is that:

Silk fibres have triangular prism-like structure, which allows them to refract the incoming light at different angles.

By my understanding, refraction takes place only when light enters another medium. (This is only for reference)

My question is: Do silk fibres allow light to pass through them?

  • $\begingroup$ If the question is not suitable for this site, I would like it to be transferred to the another site. Thanks! $\endgroup$
    – user100323
    Nov 11 '20 at 1:27
  • 4
    $\begingroup$ Patience, many of us are asleep or at work. $\endgroup$ Nov 11 '20 at 5:08
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    $\begingroup$ How is this about animal husbandry? $\endgroup$
    – MattDMo
    Nov 11 '20 at 18:28
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    $\begingroup$ @user100323 you tagged the question animal-husbandry and I simply inquired how this question and that tag were related. You are a member on enough other Stack Exchange sites that you must surely know how the tagging system works, so your plea of ignorance doesn't hold any water. The other comment was in reply to your complaining about no one commenting on or answering your post yet - not making fun at all. Here's a hint: when joining a new community, educate yourself about how it works instead of complaining about everything. $\endgroup$
    – MattDMo
    Nov 12 '20 at 0:46
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    $\begingroup$ @user100323 as for your actual question, if the reason for silk fibers' being lustrous is that they diffract light, then of course light can pass through them. The Biology.SE community has agreed that questions that show little or no prior research effort are off-topic on this site unless you have shown your attempt at an answer. Please see our homework policy for more information. Additionally, as indicated above, this is not even about biology, it's about physics. Please read the help center to learn more about this site. $\endgroup$
    – MattDMo
    Nov 12 '20 at 0:50

Yes, silk allows light through.

I did a google scholar search using terms:

optics of silk

Lots of articles, the article below measures a refractive index of about 1.54

Paywalled except abstract and figures.

Bucciarelli, V. Mulloni, D. Maniglio, R.K. Pal, V.K. Yadavalli, A. Motta, A. Quaranta, A comparative study of the refractive index of silk protein thin films towards biomaterial based optical devices, Optical Materials, Volume 78, 2018, Pages 407-414, ISSN 0925-3467, https://doi.org/10.1016/j.optmat.2018.02.058.

Found at:



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