Luster does NOT mean only shiny!

luster-not-shinyOne of my biggest issues with science teachers in schools today is that they tell kids when they are learning about rocks and minerals that term luster means shiny. Well, guess what, it doesn’t! I wrote a blog post on this several years ago and it is still happening. Again, my daughter came home from school (this time in middle school) with a paper that said that luster was “shiny.” Gag. And, if it isn’t shiny, it has no luster. Double gag.

Every mineral has a luster. Yes, the luster can be shiny but it can also be many, many other things. Geologists define luster as the way light bounces off of the surface of a rock or mineral. Some common lusters are:

  • Earthy
  • Dull
  • Greasy
  • Silky
  • Pearly
  • Shiny
  • Metallic
  • Vitreous (Glassy)
  • Resinous
  • Waxy
  • Submetallic
  • Adamantine

So, teachers and homeschool parents, PLEASE teach kids the correct definition of luster. Yes, it can be shiny but it could also be any of these other terms. Some minerals may even have more than one luster depending on the way it forms. If you have questions, just let us know. We love talking about mineral identification! You can get us at: rockinfo@minimegeology.com.

Click here to read my earlier blog post about mineral luster.

 

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