saturation – The Gemstone Project

Evaluating a Neon Pink Red Mahenge Spinel

Posted on September 26, 2016September 25, 2016 by grayspinel

This week’s blog is an evaluation of a 3.21ct Mahenge spinel that I did for a client recently. The stone was brought in from Mayer & Watt, a wholesale dealer where the advertised MSRP is $5,256/carat. The following is a direct copy and paste of my email.

Color:

It is always interesting to see how different stones look when up against other stones of similar colors. For this pear, I pulled out the large Mahenge reddish-pink cushion I have, the small Burmese pink-red, a red-red oval, my red spinel band, and my pink-pink Mahenge spinel. So this one is interesting because up against the more pink stones, it looks more red, and when it’s up against a red red, it looks pink. Overall it’s strongly saturated, medium in tone, with the slightest hint of orange when compared to pinks that are more blue-toned.

Inside

Outside

Inclusions:

My biggest concern going into it was the inclusion. As I think I mentioned in a message I sent you earlier, in some lighting situations, it’s more obvious than in others. Right now it’s about 18 inches from my face, and even though I know where it is, I have difficulty finding it. I think that it would be very close to where a prong would sit to hold it, so once set, it may become even less obvious. I just put it under 14x magnification and it looks as though there is a cluster of 3 bubble inclusions, which are typical for the Mahenge location. They don’t pose any problems for setting, they don’t even come close to reaching the surface. The largest one has a slightly larger cloud around it that’s typically not visible except when backlit, which I have attached a picture of. They are all clear or white inclusions, probably a negative crystal inclusion and two gas bubbles. Even with the three inclusions, I would say that this is a very clean example of Mahenge material.

Cut/coloration:

You had asked about zoning earlier. There isn’t any zoning, but as is pretty typical with pear and marquise cuts, the color tends to concentrate on the tips, as a result of the cut. This one is actually pretty evenly colored, with just a slightly deeper color on the tip. As far as cut, this is a really well cut pear. There isn’t any windowing, and there isn’t an abnormal amount of tilt windowing. If anything, I’d say that there is less than the typical amount of tilt windowing. There does not appear to be any bow-tie or large amount of extinction.

Fluorescence:

It glows a bright red under UV light.

Overall I’d say it’s a pretty exceptional stone. The only hesitation I would have would be the inclusion, but that’s really a matter of personal preference – I’m ok with inclusions so long as they aren’t detrimental to the overall look of the stone.

Color

Posted on January 18, 2016January 17, 2016 by grayspinel

When I was young, I really wanted to be an interior decorator. Every wall in my house was painted white, except for my room, which was a soft buttery yellow. When I was about 7 my mom decided to hire an interior decorator for this one room in our house, and I still don’t know why that room was picked, as it was the least formal communal room, containing our tv and my father’s desk. The decorator ended up wall papering one wall, and took about 6 months to coax my mom into painting the rest of the walls a light peach color. I never understood the color scheme in there, and still don’t, but I loved the idea of giving a room some personality through color, shape, texture and furniture arrangement.

I have mentioned on social media that I’ve been in the midst of home renovations. My family and I recently purchased a home that was built in the 1970s, and as a result, requires a bit of work to update the place. I’ve been getting a lot of grief about the colors I’ve chosen for the house. I really decided to go all out for this house and I’m not holding back in the color department, with deep emerald, pale periwinkles, vibrant teal, violet and a vivid green, to name some of the more exciting colors.

But I’ve come to realize that color is one of those things that’s highly subjective, and everyone’s opinion is going to vary based on a lot of factors. The most controversial color is surprising to me – a pale green. The reasons I chose it aren’t important, but the strong reactions to it have been startling – it’s a pale minty bluish green, reminiscent of Baskin Robbins’ Mint Chocolate Chip, but lighter (kind of like the above garnet). In my opinion, a pretty innocuous color.

But that’s the thing, color can have unexpected visceral reactions and people are going to love and hate the same colors, and sometimes won’t even be able to explain why they are having the reactions to the color that they are.

So here is a little bit about color terminology for gemstones. I’ve gone over some of these terms before, but it’s always good to have a refresher.

Hue: the color of the stone. “Purple” “blue” “red” “teal” are all hues.

Tone: lightness to darkness of the stone. “Deep in tone” connotes that a stone may have a darker color. “Light in tone” connotes a pale or pastel shade.

Saturation: how much color/pigmentation a stone has, the intensity or vividness of a color. “light” “medium” “intense” “vivid” are all terms that can be associated with saturation.

Modifier: if the stone has a strong primary color, the secondary (or even tertiary colors) are called modifiers.

I would describe the above spinel’s color like this: Blue in hue, with medium-dark tone, medium to strong saturation, with a slight green-gray secondary modifier. This stone also shifts to a purple under fluorescent lighting, the rest of the information stays the same in both colorways.

The most highly sought after stones in the colored stone universe are going to be pure of hue, medium in tone and with vivid saturation. A little gray goes a long way to making stones be within a more reasonable price range with typically a barely perceptible difference.

So, I’ve been posting less to Instagram, Facebook, Twitter, etc because I’ve been busy painting and painting and painting. Good thing it’s a labor of love but I will be so happy when it’s over! I have some exciting things planned for the coming weeks, including a Q&A feature with someone in the gemstone world, and a couple fantastic custom projects I’ve been working on over the last few months. I have fun stuff coming up for 2016 too, and I can’t wait to share those things with you as the year progresses!

Gemstone Vocabulary and Anatomy

Posted on July 20, 2015July 12, 2015 by grayspinel

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