How to tell if a gem has life?

[cookies]

I purchased and returned quite a few gems in the past. The main reason for the returns was, the gem didn't look lively in person. It just looked plain, dull or dead, regardless of the amount of sparkles. So I was wondering, is there a way to tell from vendor's pictures whether or not a gem has lots of life to it? If there is such a way, I would love to learn it! Neon stones are probably easier to tell than others, but they are also more expensive in general.

 

[davi_el_mejor]

I look past a lot native cut stones that don't have a good crown. Most often a flat crown means a flat dull stone. A nice crown means there is promise. But static photos can't really give you a feel, like you've seen you have to see a stone.

 

[0-0-0]

IMO unless a stone has a nicely saturated color, the cut makes all the difference.

In photos I look for high crowns, small tables, decent facet meets, crisp symmetrical facet patterns, and well cut girdles. Avoid windows and fat pavilions if you are looking for a lively gem.

 

[ChrisA222]

I didn't understand how it could look dead "regardless of the amount of sparkles". If it has a lot of sparkles, how is it looking dead??

 

[cookies]

I didn't understand how it could look dead "regardless of the amount of sparkles". If it has a lot of sparkles, how is it looking dead??

I may not have used the right words.. I once bought a sky blue topaz that was cut in the round portuguese style, no window, and had lots of sparkles due to the number of facets. But I rejected it right after I saw it. I love portuguese cut, but didn't care for this particular stone. It looked plastic-y. Perhaps it had something to do with the color saturation? I love blue and aqua blue colors though.

 

[0-0-0]

I think I know what you are talking about. I think a lot of the blue topaz sold at mall counters look plastic-ky as well. I think it may be due to poor polish. But I don't think most vendor pictures have enough resolution to show the quality of polish.

ETA: IMO the low quality concave cuts look especially plastic-ky.

 

[T L]

I didn't understand how it could look dead "regardless of the amount of sparkles". If it has a lot of sparkles, how is it looking dead??

I may not have used the right words.. I once bought a sky blue topaz that was cut in the round portuguese style, no window, and had lots of sparkles due to the number of facets. But I rejected it right after I saw it. I love portuguese cut, but didn't care for this particular stone. It looked plastic-y. Perhaps it had something to do with the color saturation? I love blue and aqua blue colors though.

Blue topaz is often a victim of poor polishing, bad luster, and machine cutting. There are some pretty ones, but there are mass produced cut ones that are not so great. I think for a stone to be truly beautiful, one must evaluate the following

Saturation
Tone
Hue
Luster
cutting
Refractive Index (the higher, the more brilliance and dispersion, especially in a nice cut and medium to medium light tone)

For example, you may have a gem that isn't precision cut, but it has nice luster and RI to make up for it, or it may have nice saturation.

As for tone, if it's too dark, I don't care about any of the above, it will not have life to it, no matter what other pluses it has.

 

[minousbijoux]

I'm glad TL brought RI into the mix. The first thing that crossed my mind when Cookie was talking about sparkle, but dead was the glassiness associated with a lower RI stone. That and bad polish. Luster is a hard concept for me to wrap my mind around for some reason, even though you can sort of equate it to whether the window is clean - and I don't mean a stone's window!

 

[T L]

Thanks Minou,
I think one should also evaluate clarity as well, forgot to mention that in my list above. A very included stone will lack life.

 

[Michael_E]

Seeing life in a stone also depends on the lights under which you are viewing it. If you are in a room with diffuse lighting, fluorescent lights and off white, satin textured walls, ( or worse, a dark room with one light source), then nothing will look lively. If you're in a room with lots of unfrosted incandescent bulbs, say at Christmas time, everything looks lively. A gem can only reflect the light which is around it, so you want to make sure that you're looking at a gem under consideration, in lighting which gives it a chance to be lively.

As for vendor pics, no it is impossible to tell if a stone will be lively from a still shot, since either the stone or lights have to be moving in order to see any sort of scintillation. It's barely possible with a video, but so many variables can be manipulated to show a stone in a way that it will never look on your hand, that any pics should only be used as a very rough guide to deciding what you want to look at in person.

 

[cookies]

TL, would you please elaborate on the "luster"? Is it the same thing as "glow" or "silkiness", like what we see in high-quality rubies, kashmir sapphire, neon tourmalines, etc?

Michael_E, thank you for pointing out that lighting condition is very important. Now I think of it, some gems do look much better under incandescent lights. For example, my alexandrite appears much brighter and shows more red and pink under incandescent bulbs. When I move it under fluorescent lights, the color bleeding occurs, which I am still learning to accept and love.

I do have a pink/purple tourmaline that I think is always bright and lively, except when I move it to a very dark room. I think I've set some unrealistic expectations for gemstones based on this one tourmaline, and that's probably why it's been a little hard for me to accept the "imperfections" of the new gems I got. What's ironical is, this tourmaline is not precision cut.. it's shallow, and has a big window and some inclusions. I guess it "has nice luster and RI to make up for it", and has "nice saturation", as TL puts it.

 

[T L]

TL, would you please elaborate on the "luster"? Is it the same thing as "glow" or "silkiness", like what we see in high-quality rubies, kashmir sapphire, neon tourmalines, etc?

Michael_E, thank you for pointing out that lighting condition is very important. Now I think of it, some gems do look much better under incandescent lights. For example, my alexandrite appears much brighter and shows more red and pink under incandescent bulbs. When I move it under fluorescent lights, the color bleeding occurs, which I am still learning to accept and love.

I do have a pink/purple tourmaline that I think is always bright and lively, except when I move it to a very dark room. I think I've set some unrealistic expectations for gemstones based on this one tourmaline, and that's probably why it's been a little hard for me to accept the "imperfections" of the new gems I got. What's ironical is, this tourmaline is not even precision cut.. it's shallow and has a big window. I guess it "has nice luster and RI to make up for it", and has "nice saturation", as TL puts it.

Luster is how light reflects off the surface of a stone. Some gems, simply by the nature of their makeup, have a dull, waxy, or what one would say, a "glassy" luster. Harder stones, especially those with a high RI, have a 'adamantine' or 'semi-adamantine' luster, like diamond. The shine off a diamond's surface is very bright. Some lapidaries spend a great deal of time polishing to help make a more beautiful luster. Here's a very good article on luster. I think luster is a very overlooked quality, and it should be considered when looking for a gem with life.

http://en.wikipedia.org/wiki/Lustre_(mineralogy)

BTW, tourmaline is not a high RI gem. Diamonds are, hence the greater dispersion, more brilliance, and smaller tilt windows seen in cut and polished gems.

 

[0-0-0]

Luster and RI certainly play a role when comparing different types of material. But when looking at why a stone looks more lively next to other stones of the same material, especially typically cleaner material with minimal inclusions like beryls and topazes, the quality of faceting and polish makes all the difference.

 

[chrono]

Based on your example of blue topaz, it is likely to be due to poor polish since it has no cut or colour issues. Blue topaz is irradiated so usually the colour is quite intense. Perhaps that could contribute to the fake look as well, unless you are getting the very pale version.

The usual suspect of poor performance is sometimes the colour (low saturation and / or dark tone), cut issues (low crown, overly deep belly, windowing), finish (polish) and material characteristic (low RI and lustre). As for the last example, although spinels don't have high RI like demantoid garnets and diamonds, what saves them in light to medium toned spinels is the lustre.

 

[cookies]

Thank you everyone. So I am going to try to pay more attention to the luster and the polish from now on, in addition to a lot of other contributing factors, including RI, cut, window, body weight, crown height, tone, saturation, etc.

TL, the article about the luster is quite educational. I just learned that the higher the luster, the higher the RI. Is a stone more likely to have a good luster if it has a high RI?

 

[T L]

Thank you everyone. So I am going to try to pay more attention to the luster and the polish from now on, in addition to a lot of other contributing factors, including RI, cut, window, body weight, crown height, tone, saturation, etc.

TL, the article about the luster is quite educational. I just learned that the higher the luster, the higher the RI. Is a stone more likely to have a good luster if it has a high RI?

To your last question, I never really paid attention to the RI relationship to luster, but now that you mention it, there seems to be a relationship, but I don't want to say that with 100% surety. Some high RI materials also give off a metallic or semi-metallic luster too.