The Best Examples of Luster in Minerals

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All minerals have luster as one of their properties.  The definition of a minerals luster is the general ability to reflect light from its surface.  The smother and clearer the surface of a mineral, the better the quality and intensity of light will reflect off it.

Some of the best examples of mineral luster will be the minerals that express greater light reflection.  Shiny minerals catch the eye and many love the sparkle they bring.  However, not all minerals will have a shiny reflective surface and will fall into some different categories of luster. 

Before I get into some of the best examples of luster in minerals, I want to quickly call out the types of luster you will find with a mineral.

There are two types, or categories, of luster; metallic and non-metallic: 

A metallic luster by definition stands on its own as a reflective surface containing metal.  Non-metallic luster has several sub categories apart from a metallic luster.  The main difference between a metallic luster mineral and non-metallic luster mineral is metallic luster minerals have reflective metal within its contents.

For purposes of talking about the various luster types a mineral has, I will forgo compartmentalizing the non-metallic types.  I will not refer to any luster type as a sub category of the non-metallic type.  Just know that the two categories do exist.     

10 Types of Mineral Luster

Types of Mineral LusterLuster Appearance
Adamantine                                       Sparkly, high gem quality.
Dull or Earthy   Not much of a reflective surface.
Greasy Looks greasy.
Metallic Very shiny metallic look.
Pearly Has a look of a pearl.
Resinous Looks like resin, sap, or honey.
Silky Has a look similar to silk.
Submetallic Has a metallic look but not highly reflective.
Vitreous Glassy look.
Waxy Has the look of wax.
Types of Luster in Minerals Table

Identifying a minerals luster does not typically require any tools to be observed except your eye sight.  In some cases you may need to use some magnification for better clarification.  For the most part you can visually look at a mineral and come close to identifying what luster it might have.

With these categories of luster, let’s go over some of the best examples of luster you will find for each one.  As a note, most minerals do not express only one type of luster.  It is important to also know that luster is not a catch all for identifying a mineral.

Adamantine Luster

Adamantine luster is considered to be the most reflective luster of all the luster types.  The best example of adamantine luster will be the diamond.  A diamonds unique properties and composition allow for this highest of grades of luster.

Some say the luster of a good diamond is unbeatable.

An adamantine luster mineral needs to be very brilliantly reflective with lots of sparkle.  Only a few other examples of adamantine luster minerals such as cerussite, cubic zirconia, and zircon, will commonly express this type of luster.

Dull or Earthy Luster

Some of the best examples of dull or earthy luster are graphite, limonite, moganite, kaolinite, and montmorillonite.  Minerals with dull or earthy luster express little to no reflective light at all. 

For a mineral to express the luster of dull or earthy they need to be porous, granular, or very rough.  Many minerals will express a vitreous to dull luster, which can make it difficult to identify a mineral based on this property alone.

Cinnabar is a great example of a dull and shiny mineral.  This mineral can be at the top of shiny, expressing an adamantine luster.  In contrast, a very different specimen of cinnabar can express a very dull luster.

If you are interested in seeing some good pictures and information on cinnabar, go to my article “All About Cinnabar“

Greasy Luster

Examples of minerals that have a greasy luster are chalcedony, chrysocolla, colimaite, and cordierite.  Minerals of this type of luster feel “greasy” when touched.  Though no greasy residue of any sort is left behind on your fingers.

Greasy luster minerals can be visually identifiable as well.  They can have a look of “greasy-ness”.  They can appear kind of dull looking but often have the appearance of some minor transparency.  Almost as if you can polish them up and give them a shine.  

Often there are rocks, with minerals, that have that greasy look.  Some of those greasy luster rocks are serpentine, flint, and chert.

Nice piece of polished serpentine. Though not considered a mineral, but a rock, it will often have a greasy luster. This specimen looks and feels greasy.

Metallic Luster

The most notable examples of metallic luster in minerals are, bornite, chromite, galena, pyrite, hematite, magnetite, chalcopyrite, and chalcocite.  Native minerals such as copper, gold, and silver are also good examples of having metallic luster.

Not all minerals with metal in them will have a metallic luster.  Some mistakenly think because a mineral has metal in it, that it must have a metallic luster.  For a mineral to be considered as having a metallic luster, it must have a reflective metallic surface.

A chemical bond that creates a smoother surface along with higher concentrations of metal, will generally yield a more metallic reflective surface.

Who can deny that pyrite is one of the best examples of a shiny metallic luster mineral.

Shinny metallic luster surfaces area favorite for many. For great references on some of these metallic luster minerals I have written articles going into a little more detail about them. Click on the links just above to find out more.

Pearly Luster

Some of the best examples of pearly luster minerals are calcite, mica, talc, gypsum, and muscovite. Pearly luster minerals will have thin transparent sheets along the same plane.  The way light reflects off these sheets gives them that pearly look.

You don’t see it too often, but I have heard that sometimes pearly luster is also referred to as nacreous luster.  By the name “nacreous”, I think you can see why it is not often chosen over “pearly”.

This is an example of selenite.  Selenite is a type of gypsum which has a pearly luster.  Selenite is very popular in the rock and mineral collecting world.  Much of that is likely due to its pearly luster.

Resinous Luster

Resinous luster minerals will express the appearance of honey, resin, or sap from a tree.  Some good examples of resinous luster minerals are amber, sphalerite, pyrochlore, aragonite, beryl, and some garnets.  Resinous luster has a mid-range reflectance surface with transparency.

It’s been said that a lot of resinous type minerals will end up being yellow, oranges, reds, and browns in color.

This garnet appears to be a combination of almandine garnet and spessartine garnet (has a little bit of orange in there).  Generally garnets are classified as vitreous to resinous luster.

  

Silky Luster

Examples of silky luster minerals include actinolite, ulexite, asbestos, tigers eye, pectolite, satin spar, and fibrous malachite.  Silky luster minerals will have very fine fibers which make their appearance look like silk.

Yuksporite is a rare mineral with a vitreous to silky luster.  Not many know about this mineral but it contains some of the rare elements of niobium, strontium, and titanium.

This is an un-polished specimen of tiger’s eye (left), next to a polish tiger’s eye (right).  Polished tiger’s eye will often carry the luster definition of silky-vitreous.  In Tiger’s Eye, very tiny fibers will often follow each other in a general direction.  Often, the different colors of browns, oranges, and yellows don’t follow the direction of the fibers.

   

Submetallic Luster

Often submetallic luster minerals can also be metallic luster minerals.  Some examples of submetallic minerals are chromite, graphite, hematite, magnetite, sphalerite, and wolframite.  These types of minerals are similar to metallic luster minerals, but are not as reflective.

Submetallic luster will not express the same high metallic luster in say a shiny specimen of pyrite.  These minerals are usually more porous or have rough surfaces that do not reflect light as good.

Submetallic luster is often lumped in with metallic luster as a sub group.  So you would have metallic luster, submetallic luster as a sub group, and nonmetallic luster.  Nonmetallic luster is every other type of luster that is not metallic luster or submetallic luster.

This is a tumbled piece of hematite.  You can see where some parts of the specimen would be more of a metallic luster while other parts of the specimen would have more of a submetallic luster.

Vitreous Luster

Vitreous luster minerals are perhaps the most popular minerals due to their highly reflective surface.  Emerald, fluorite, sapphire, ruby, amethyst, tourmaline, topaz, quartz, dioptase, and garnets are great examples of vitreous luster minerals.

Minerals that express a high vitreous luster are generally used in jewelry for their shiny reflective eye appeal.  This of course will go hand in hand with the mineral having nice color and being hard enough to cut without breaking easily.

Topaz is a perfect example of a vitreous luster. These specimens were found on the ground by the sparkle they gave from the sunlight.

For reference on some of these vitreous luster minerals I have written articles going into a little more detail about them. Click on on the links just above to find out more.

Waxy Luster

Great examples of waxy luster minerals include agate, chalcedony, variscite, opal, serpentine, and turquoise.  These minerals will express a waxy looking appearance.  Often waxy luster minerals will be translucent and reflect that nice waxy look.

Many waxy luster minerals will take a good polish to improve its appeal.  Once these minerals are polished they will bring out the beauty of the color within the mineral.

 

Agate and chalcedony will often express a waxy translucent appearance.  When tumbled or polished, they can show off some great eye appeal making them very popular for collectors. This is a cabochon of crazy lace agate.

Conclusion

I could not even begin to scratch the surface of the various types of minerals expressing various types of luster in one article.  There are even some other types of luster that are not mentioned very often, of which I did not cover here.  I do hope I have given you some of the best examples of luster in minerals with the commonly known types of luster categories.

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