Gemstone Vocabulary and Anatomy

I decided to put together a glossary of sorts of gemstone terms, or terms that I use relatively often and might not be familiar to those who aren’t well versed in gemstone and jewelry terminology. Something I wish I had when I was first learning!

This is an endlessly growing and changing document, and will need continuous updates to keep it useful. Please let me know if any suggestions for terms, or comments you might have!

Adularescence – milky glow that moves as the stone moves, originates from within a gemstone and is caused by inclusions, occurs in the presence of stronger light conditions.

bezel set – a way of setting a stone with solid metal completely surrounding the stone, pushed down over the stone’s girdle

brilliance – amount of light reflected back out of a gemstone, a direct result of a stone’s refractive index

brilliant cut – a facet design radiating from the culet of the stone, on a perpendicular plane from the girdle of the stone

cleavage – tendency for a mineral to break along distinct planes dependant on how the mineral grows

colorless – a stone that is not known for being without color, having zero saturation. Examples: sapphires, spinels, garnet, tourmaline, topaz

crown – the facets from the girdle up to the table, the height from the girdle to the table

culet – the pointed tip of a stone formed by pavilion facets. Antique diamonds may have “small” “medium” or “large”. Modern cut diamonds typically do not have a culet, the pavilion facets meet at a point.

dispersion – the ability for a gem to divide the light into spectral colors

facets – a flat plane cut onto a gemstone

fat belly – when a pavilion is cut to preserve weight, instead of forming a cone, it is more bulbous and round on the bottom

fire – see dispersion

fluorescence – reaction of trace minerals causing the stone to glow a specific color when exposed to UV light, typically blue, yellow and red

girdle – the circumference around the stone where the crown and the pavilion facets meet, it can range from very thin to very thick, and can be faceted or rough.

keel – an edge formed by pavilion facets. typically found in elongated cut stones

kozibe effect – culet reflected around the stone

luster – light reflected from a gem’s surface

meet – the edge in which is made when two facets line up in faceting

monochrome – varying tones of one color, white-gray-black

MRB – modern round brilliant

OEC – Old European Cut

OMC – Old Mine/Miner’s Cut

pavilion – the bottom part of the stone, typically cone shaped

pleochromism – the characteristic of having different colors visible from different angles

RI – refractive index

Rose cut – stone cut into a dome type shape with a flat bottom/no pavilion, and the crown is a hexagon shape with triangular facets, meeting in a low angled point on top, typically cut in a round shape, but may also be cushion, pear, oval or marquise.

saturation – how pure and intense a color appears. Low saturated tends to be gray, highly saturated is vividly colored.

silk – the appearance of a stone looking slightly cloudy, which bounces the  typically caused by inclusions referred to as silk,

spread – the size of a stone when looking top down, measured by the diameter of the girdle. Typically used to compare one stone to another.

step cut – a facet design on a parallel plane from the girdle of the stone, typically angular in shape. Emerald, baguette, carre, asscher are common types.

tilt window – when a stone is viewed at an angle that is not straight down into the stone, and you can see through the pavilion

table – the flat top facet of the stone

window – when a stone is cut at the wrong angles for it’s type, the see through portion in the middle is called a window

Pad5
Window illustration

Advertisements

Design: Red Spinel

I had been trying to figure out how to set this red spinel from Peter Torraca for years when I gave up and sold it.

I still worked on sketch ideas. I figure that sketches are never wastes of time, they might come in handy for other projects, which is why I have entirely too many sketchbooks lying around. I really had no idea and just went random places with it.

Red1

This was a fairly awful sketch because the outline of the stone is so way off, but it was more to get a feel for the general idea. Drawing is so hard for me to do well, and I have to spend a lot of time working on it. Drawing abnormal shapes are hard. Circles and squares are great, but throw in cushions or any cut corners and I’m screwed.

Red2

This one is actually much better but because of the angle the picture was taken, it looks a bit off. I was really running with the baguette idea at this point, but wanted to stick with the repeated patterns of the art deco period.

Red3

So I sort of switched gears from the halo and round melee and went to strict Art Deco. It was at this point where I bought the stone back from the person I sold it to, and I started to really think about how I’d really want to set it. I was playing with proportions here. The stone is smaller, so it felt like the baguettes would need to be impossible proportions to go with the look I like. I love the skinny look of the one on the bottom, and the top one is too wide, which is ridiculous because the stones are 2mm.

Red4

This is what I decided on. Fully anticipating a hefty custom setting bill, I figured I’d maybe put it at the bottom of the list to set, or end up selling it.

Red

And then I found a ring that was basically perfect, and for a ridiculously awesome secondhand price, set the red spinel in a super nice turn-of-the-century setting that was very similar to what I was wanting for it – a bunch of step cuts.

4

Feature: Lang Antique & Estate Jewelry, Bonus!

So I took a ton of photos while I was at Lang Antique & Estate Jewelry , but some didn’t come out as well as I hoped. Here are a few pieces that I was able to take more than a couple seconds to get a quick snapshot.

I don’t typically love trillions for myself, but I thought this ring was really interesting and wonderful because of the flow of the design and the way it all melds together into one giant piece of stepcut and brilliant cut awesomeness. I love the graduation of the step cuts and how they mimic the lines of the trillion, giving the whole piece an Art Deco vibe.

9

I don’t think this one really needs any commentary.

11

I loved this little band, it really had some great details to it.

14 15 (2)

I absolutely fell in love with this necklace. The larger of the two stones was a low colored diamond with the smallest table I have ever seen on an antique stone, and as a result was super fiery and all around fabulous. I thought it was the perfect size to be able to wear it on a daily basis and not have it be too overwhelming of a piece, easy to dress up and dress down. I believe the total weight on it between the two diamonds is around 1.1cts.

17 (2) 16 (2)

And for the Grand Finale!

This is in the store window. It is almost 7cts of magnificent French Cut brilliance and it is one of the most fabulous items I have ever seen in real life (having been NYC and seen the Tiffany Diamond in all it’s glory, I think that’s probably a pretty big compliment!). This stone is interesting because a hole was drilled directly into the stone and a ring through it, to hang it on a chain. You don’t see this done a lot with diamonds, especially not of this size and cut. I am guessing it was done because of an inclusion, but obviously I was not the person to do it to the stone, so I can’t really say why it was done. I would like to see it on a different chain though, rather than this round diamond chain. I feel like such an amazing and expensive diamond should have a custom piece built around it.

15 16

17 18

Next time, I’m going to have to set aside another hour, and I plan to try on everything that I saw in the front window. Ok, maybe I might need two hours…

Ok, that’s really it for my visit to Lang! Hope you enjoyed the pics, next time I’ll get video of the big french cut in action!

Feature: Lang Antique & Estate Jewelry Inside

The Lang interior consists of about 3 larger cases of diamond rings. When we finally got inside, they were full of customers, so we waited our turn while chatting with the salesperson assigned to us. She told us that they will be moving just down the street to a new larger location, but that they don’t know when construction will be finished. She also told us that lately they haven’t been able to keep any blue zircons in the cases. We hypothesized that it may be due to the popularity of Paraiba tourmaline and teal colors in general being very popular right now. I wonder if buyers are educating themselves more and discovering that zircon is not the same thing as cubic zirconia.

Anyway, we tried on some diamonds, and my friend particularly fell in love with this cushion. I think her boyfriend might be getting a link or two in his email…

1

2

We were on the side with the larger diamonds, but nothing quite like the honkers in the store windows.

3

This was only part of one case.

4

5

Beautiful profile view of a ring. The dark stones are actually bright blue sapphires. My white balance got screwed up when I was snapping the picture, but the other pictures were blurry.

6

A beautifully patterned OEC ring.

7 8

A massive ball of step cuts. even though I love step cuts, this one didn’t really do anything for me. I think the proportions of the sidestones bothered me. I like to have more of an extreme taper. I think the trapezoids compete with the center stone.

9

A large marquise cut stone, the profile was gorgeous, and looked a bit like a boat.

10

Both my friend and the salesperson really liked this ring on me, but I always see an eyeball when I see rings like this.  I can’t help it!

1112

I don’t particularly like fishtail prongs, but between the beautiful center stone and the french cut sides, this ring really wanted to come home with me.

13

 

I have to say though, I was disappointed to hear that they will not sell any stones loose. Nor do they sell settings separately. Also, the prices are astronomical, compared to other retailers of fine antique jewelry.

That about sums it up for the visit to Lang. I’m so glad I got to go! I saw so many beautiful jewels, and had a fantastic time with a very good friend! I wish we had been able to spend more time looking around and trying things on, but their little store was completely packed and neither of us was going to be buying that day. It was really fun to see what different size diamonds look like, and to judge the cut quality on so many different stones at once. I would highly recommend it if you’re going to be visiting San Francisco and want to get a good antique jewelry fix!