How do YOU think of the term, luster?

[kenny]

Even though I hear the term often I'm not sure of the meaning because often when luster is used I just don't see a consistent characteristic.

Please don't look it up. or read others' posts; just post the first thing that comes into your mind.
I'm not trying to force a single universally-agreed-to meaning, or send anyone to a dictionary.
Rather, without Googling, please just write how YOU define luster right now, without worrying that someone else may post something more "correct".

Also, to YOU, do different gems have a different kind of luster?
If so, can you offer some examples, i.e., gem A's luster is more X and gem B's luster is more Y.

Thanx.

 

[Daisys and Diamonds]

luster as in pearls
hmm
for me like a silly sheen but with depth
not necessarily shinny,
hhh .... i have the word on the tip of my tounge

 

[yssie]

I think the same as you, Kenny: It’s an overloaded term and I appreciate when people make the effort to disambiguate.

To me the word means “evaluation of specular reflection off the gem’s exterior surface”. However, that’s a very precise and limiting definition and that’s not what it means to most anyone else!

In the pearls world it’s an umbrella for glossiness, contrast, glow, and iridescence.

 

[Gloria27]

Luster for me is how reflective a gem or a pearl is, the intensity of the shine. For pearls is how clear/sharp you see your reflection in them and for gems, how much diamond-like the outer facets reflect, like a mirror. The higher the luster and the darker the colour, the less you see inside because you see more mirror like reflections of the surroundings.
This is what luster is to me.


Yes different gems have different luster, my Chrysoberyls are more diamond-like than my Beryls. Beryls are more see-through, more water like. Chrysoberyls are like a disco ball, they have fire too.

 

[Nick_G]

To me it's the manner in which light is reflected from a surface. Simple as that.

 

[chrono]

To me it's the manner in which light is reflected from a surface. Simple as that.

Ditto this.

 

[MamaBee]

I think of it as a shimmer from a surface.

 

[Rfisher]

Not helpful

But when I read the term luster
All I think is
L@@K!! AAA+++ gOrGeOuS LUSTER !!!!!!!
eBay type gemstone listings

 

[marymm]

To me, "luster" refers to how the gemstone's or pearl's surface looks when light hits it.

And, yes, to me, the luster will look different on various gemstones and pearls -- meaning both that two otherwise similar pearls or gemstones of same variety may well have different luster, and that the luster of a pearl will look different than the luster of a clean faceted gemstone which will look different from the luster of a silky/sleepy gemstone which will look different from the luster of a jadeite cabochon which will look different from the luster of a moonstone ... you get where I'm going ... luster is a key factor in my evaluation of any stone/pearl purchase ... sometimes a sharp mirror-like luster is what I'm seeking, sometimes a shimmery 3D-ish luster is what captures my heart.

 

[CaseyLouLou]

To me luster is the surface shine or level of polish. But I see it used in listings as a way to describe the sparkle which I think is supposed to be something else like scintillation. I have never really understood the term luster so I don’t pay much attention to it in listings.

 

[Autumn in New England]

What an interesting topic! I loved reading everyone's responses. This is a perfectly simple definition of luster, for professionals or laymen alike.

To me it's the manner in which light is reflected from a surface. Simple as that.

Speaking in terms of the first thing I think of when I hear the word, it would be when I studied at the GIA. They drill those categories into your head... adamantine, vitreous, greasy, etc. I remember thinking that had to be nonsense, but some gems really do look oily, like some varieties of jade and orange opal!

 

[T L]

I think luster is a subjective term, based on the responses, but it is also a very underrated part of a gemstone. The shine or mirror like reflection off of a gem surface can be quite alluring, as well as sharper facet edges, you get incredible sparkle off the surfaces, or reflections that emphasize the beauty of the facet work. There is added scintillation going on with gems of fine luster.

To best describe how I see luster, I think gray spinels are a huge thing primarily because of their luster, and the RI of spinel. Imagine a faceted gray piece of glass, it’s not anywhere near as tantalizing as a gray spinel. The luster adds a special sparkle factor.

I love the color of apatite, but truth be told, the luster is very blah, so I think the gem would be far more beautiful with finer luster.

Here are some shots that really had me mesmerized when I saw these gems shine off the surface. It’s best experienced in person of course. Photos just don’t do fine luster justice.





Many people mentioned pearls, while iridescence is very important, the more of a mirror like shine, also enhances the value. Some pearls can look dull, but that mirror like surface is special as it’s entirely made by the oyster. It’s different than the added scintillation of faceted stones, but more of an overall mirror like effect.

Lapidaries of course need credit. Without good polish, you won’t have good luster.

 

[Autumn in New England]

Lapidaries of course need credit. Without good polish, you won’t have good luster.

Gorgeous examples, as usual, T L! I especially agree with this last part ^ .

 

[thirdrock]

for me like a silly sheen but with depth

I was going to say almost the same thing. I think of it as a reflective sheen with depth.

 

[fredflintstone]

Luster is the shine. A high polish makes a stone more lustrous, can make a stone look wet. The harder the stone the better the polish it will take, hence the more luster it has if polished well.


Think of Pearls. What is the main selling point on pearls?

Their luster.

 

[Gloria27]

What an interesting topic! I loved reading everyone's responses. This is a perfectly simple definition of luster, for professionals or laymen alike.



Speaking in terms of the first thing I think of when I hear the word, it would be when I studied at the GIA. They drill those categories into your head... adamantine, vitreous, greasy, etc. I remember thinking that had to be nonsense, but some gems really do look oily, like some varieties of jade and orange opal!

Exactly
adamantine = comes from greek word adamas referring to a hard substance which some believed it was diamond (the adjective is adamantinos)

That's where the inspiration for the word Adamantium came from, the metal alloy Wolverine's skeleton was replaced with, which was almost indestructible.


Forgot to mention the word diamond comes from the latin word diamas and diamas in another word for adamas.

 

[Autumn in New England]

That's where the inspiration for the word Adamantium came from, the metal alloy Wolverine's skeleton was replaced with, which was almost indestructible.

This may be the coolest bit of trivia I've ever learned here on PS!

 

[Gloria27]

This may be the coolest bit of trivia I've ever learned here on PS!

I'm an adult who watches superhero movies...that's right.

 

[Autumn in New England]

I'm an adult who watches superhero movies...that's right.

Same! And children's cartoons!! @Daisys and Diamonds now has me hooked on an animated UK show called "Postman Pat." I've been binging it the way some folks binge GoT. I always say to my brother, "God we are so immature!" And his response every time is, "I know, isn't it glorious?"

 

[MrsBlue]

Soap bubbles. Smooth and glossy with iridescence. That's luster to me.

 

[Daisys and Diamonds]

I'm an adult who watches superhero movies...that's right.

in this house our favourite is the man of steel but i also have a soft spot for Diana Prince
just love her bracletes

 

[LilAlex]

Like others above, I do think of it in terms of reflected light. I (objectively) know it is an intrinsic property of the material but I struggle with how much of the phenomenon is related to non-intrinsic properties like the quality of the polishing, etc. On vendors' IG posts, luster seems to mostly mean "sparkliness" -- which opens its own can of worms...

 

[Autumn in New England]

Like others above, I do think of it in terms of reflected light. I (objectively) know it is an intrinsic property of the material but I struggle with how much of the phenomenon is related to non-intrinsic properties like the quality of the polishing, etc. On vendors' IG posts, luster seems to mostly mean "sparkliness" -- which opens its own can of worms...

You bring up a good point... glass can be polished to a high shine, but its true luster will usually (with the exception of fine crystal) pale in comparison to that of a natural vitreous gem like amethyst. So then luster, IMO, must be intertwined with polish quality and also intrinsic properties such as hardness, and RI and dispersion (in transparent gems). I agree with you... it's complex.

As you said, many vendors, especially Asian ones, seem to use luster and brilliance (or fire) interchangeably. I pretty much ignore those selling terms at this point.

 

[yssie]

This is pearl-specific.

Here’s a 2017 paper that goes into some definitions of the word “luster” in detail - it actually uses the same terminology as a decades-old paper on wall paints. Linked below and PDF attached.

This was helpful for me - to deconvolve the word for myself - but in practice no one uses this sort of verbiage (or even these sorts of ideas) to sell or buy pearls. Nor should they, but I’d love to see a happy medium reached between pedantic and today’s general usage

https://www.researchgate.net/publication/328550037_Tahitian_Pearls'_Lustre_Assessment

 

[fredflintstone]

This is pearl-specific.

Here’s a 2017 paper that goes into some definitions of the word “luster” in detail - it actually uses the same terminology as a decades-old paper on wall paints. Linked below and PDF attached.

This was helpful for me - to deconvolve the word for myself - but in practice no one uses this sort of verbiage (or even these sorts of ideas) to sell or buy pearls. Nor should they, but I’d love to see a happy medium reached between pedantic and today’s general usage

https://www.researchgate.net/publication/328550037_Tahitian_Pearls'_Lustre_Assessment

But, no one would buy a pearl if it did not have luster. It would be dull.

 

[yssie]

But, no one would buy a pearl if it did not have luster. It would be dull.

I don’t follow - I’m not saying avoid “luster”? Or at least that’s not what I’m trying to say... The term “luster” is used to describe all the effects outlined in that article and more. But it’s used very inconsistently - different people use it to mean different subsets of all of those effects… But different people also value different subsets of those effects more highly, and currently there’s no common language for buyer and seller to explicate which properties of “luster” are desired/present…

 

[fredflintstone]

Like others above, I do think of it in terms of reflected light. I (objectively) know it is an intrinsic property of the material but I struggle with how much of the phenomenon is related to non-intrinsic properties like the quality of the polishing, etc. On vendors' IG posts, luster seems to mostly mean "sparkliness" -- which opens its own can of worms...

No piece of gemstone rough has the luster that it has once polished. Polish brings the luster out by smoothing the surface of pits, cracks, bumps, roughness, what have you, that interfere with the reflection of light on the surface of the stone. The better the polish the better the luster.

 

[T L]

You bring up a good point... glass can be polished to a high shine, but its true luster will usually (with the exception of fine crystal) pale in comparison to that of a natural vitreous gem like amethyst. So then luster, IMO, must be intertwined with polish quality and also intrinsic properties such as hardness, and RI and dispersion (in transparent gems). I agree with you... it's complex.

As you said, many vendors, especially Asian ones, seem to use luster and brilliance (or fire) interchangeably. I pretty much ignore those selling terms at this point.

Also many gems don’t retain their luster, as they’re softer and can be prone to losing their polish. Diamonds are best at retaining their luster due to hardness.

 

[Autumn in New England]

Also many gems don’t retain their luster, as they’re softer and can be prone to losing their polish. Diamonds are best at retaining their luster due to hardness.

Yep, hardness has to be a component. Another example would be turquoise, which typically has a waxy luster. Of course, it's opaque, so RI and dispersion aren't really going to be factors. But its hardness is of great importance with regard to luster. I'm strictly speaking in terms of natural (unstabilized) turq. As all turq collectors know, the harder the variety of turq, the better the polish. The better the polish, the better the luster. Soft turq will never come to a high polish (without treatment), and will always have a dull luster as result. So these aspects cannot be totally compartmentalized. They're all interrelated. Great topic and discussion!

 

[Nick_G]

Exactly
adamantine = comes from greek word adamas referring to a hard substance which some believed it was diamond (the adjective is adamantinos)

That's where the inspiration for the word Adamantium came from, the metal alloy Wolverine's skeleton was replaced with, which was almost indestructible.


Forgot to mention the word diamond comes from the latin word diamas and diamas in another word for adamas.

Adamantium has nothing to do with this guy then?: