emerald, emerald enhancements, Opticon, gemology, oil treatment
emerald, emerald enhancements, Opticon, gemology, oil treatment

The Digital Devil: Don’t Forget to Flush
by Richard W. Hughes

And ye shall know the truth and the truth shall make you free.

[Biblical saying inscribed on a wall of the main lobby at CIA headquarters, USA, where the truth only seems to makes the inhabitants nervous]

It started small. Probably a joke at the office water cooler. Rumor was that the US Postal Service was lobbying to put a tax on e-mail. Next thing you know, angry messages are flying around the world and I'm dusting off my bazooka for an assault on the Capital building. That is until I found out it wasn't true. It mighta been true, it coulda been true, oh it shoulda been true, but alas, it simply wasn't. Damn!

Pope-a-dope

Beliefs. We guard 'em closely. We bow down to them, defend them to the death. We are Pope Paul V railing against Galileo's Copernican astronomy. Don't know if you're like me, but once I get an idea in my head, it takes over like some kinda virus. All of a sudden, it's down with the godless commies, pox on the infidels and the next thing you know, I'm whistling the David Koresh death march…

Puzzling

A number of years ago an article in the Skeptical Inquirer appeared about a puzzle sent in to Marilyn vos Savant of Parade magazine, a woman who Parade bills as (and who probably is) one of the smartest people on the planet. Here is the gist of the challenge, which I'll refer to as the Three Doors Puzzle:

You are on a game show and are asked to pick between three doors. Behind one of the doors is a million-dollar prize, behind the other two is either a date with Linda Tripp (for the boys) or Ken Starr (for the girls). I am the host and I know what is behind each door and will obviously try to keep you from winning.

I ask you to choose a door and, let's say, you choose Door #2. Now, I open Door #1, revealing none other than Ken Starr. At this point, I ask if you would like to switch your choice. Here is the question:

  1. Is it better to switch?
  2. Is it better to stay with your original choice?
  3. Does it make a difference in your ability to win?

If you are similar to 99.99% of the sapient human populace, you've chosen either the second or third option. So dust off the microphone and dark glasses, baby – you're off on a date with Linda Tripp.

Yes, it's hard to take, but it's true – the best choice is to switch. Think about it. Do the math:

  1. The prize is behind Door #3. You first choose Door #2 and so I open Door #1 (I will certainly never open the door with the prize behind it). Out pops Ken Starr. If you stay with Door #2, you lose, if you switch to Door #3, you win.
  2. The prize is behind Door #1. You first choose Door #2. I know where the prize is, so this time I open Door #3. Out pops Linda Tripp. If you stay with Door #2, you lose, if you switch to Door #1, you win.
  3. The prize is behind Door #2. You first choose Door #2. I know where the prize is, so I open either Door #1 or #3. If you stay with Door #2, you win, if you switch, you lose.

Result? If you switch, you win two out of three times. If you stay, you win one out of three times.

All of a sudden it's down with the godless commies, pox on the infidels and the next thing you know, I'm whistling the David Koresh death march…

Shell-shocked

Ever heard of the three-shell game? Now you have. People lose not because their eye is too slow to follow the pea, but because the obvious answer is simply wrong. In this case, the truth goes against all our gut instincts.

With the above in mind, pause here for reflection on a bit of gemological dogma. Numerous folks (including the present author) have stated that when filling a crack or fissure in an emerald, the refractive index (RI) of the filling material is critical. The more closely the RI of the filler is to the RI of the emerald, the better the filler masks the inclusion. Our gut tells us it's so. Which brings me to my second game.

Below you will find photo pairs of five different emeralds both before and after filling. The fillers have RI's of 1.500, 1.517, 1.531, 1.550 and 1.570, while the stone's RI's range from 1.569 to 1.580. In each case, the untreated stone is on the left, while same stone after treatment is on the right. Your job is to guess the RI of the filler in each stone. Arrange the letters of the emerald pairs from lowest to highest RI and write down your answer on a piece of scratch paper. Keep in mind that we are rating the ability of the filler to mask the inclusions, not choosing which stone is the cleanest or looks best after filling. In other words, rate the stones by how much improvement you see between the before and after photos. If the theory is correct, the stone that shows the greatest improvement should have the highest RI filler.

emerald, emerald enhancements, Opticon, gemology, oil treatment

A.

emerald, emerald enhancements, Opticon, gemology, oil treatment

B.

emerald, emerald enhancements, Opticon, gemology, oil treatment

C.

emerald, emerald enhancements, Opticon, gemology, oil treatment

D.

emerald, emerald enhancements, Opticon, gemology, oil treatment

E.

Emeralds before (left) and after (right) fracture filling with various oils/resins. The fillers have refractive indices (RI's) of 1.500, 1.517, 1.531, 1.550 and 1.570, while the emerald's RI's range from 1.569 to 1.580. The above photo order is random. Try to arrange the stones in order from lowest RI filler to highest RI filler. (Photos ©1999 Maha Tannous/GIA-Gems & Gemology; used with permission)

All done? Okay, check your answer at the bottom of the column by clicking here. How'd you do? Missed at least one, didn't you. If you're like most people, you missed more than one. Some people I've tested this on missed all five.

So what does this tell us? Something that should be obvious from even a cursory glance at the above photos. There is a tremendous difference between a filled and an unfilled emerald. None of us would have any difficulty separating the filled from the unfilled emeralds. But between the various fillers, there is not a significant difference in appearance, at least to the naked eye.

Some people I've tested this on missed all five…

A while back I decided to put some math behind the heresy that the RI of a crack filler isn't such a big deal. And since I couldn't ask Marilyn, I asked the smartest people I knew for help. These were John Emmett and Karen Palmer of Crystal Chemistry. They created a spreadsheet for mathematically calculating the exact amount of reflection between an emerald and a oil/resin-filled interface (it can be downloaded at this link). Below are the numbers for various fillers in an emerald with an RI of 1.58 (interested readers can see the math behind this at: www.ruby-sapphire.com/cloak-dagger-opticon.htm).

Filler RI

Critical Angle

Reflectance Percentages at Various Angles of Incidence (to the normal)

   

10°

20°

30°

40°

50°

60°

70°

80°

90°

Air n = 1.000

39.27°

5.05

5.07

7.42

100

100

100

100

100

100

100

n = 1.500

71.89°

0.07

0.07

0.07

0.08

0.11

0.25

1.05

17.01

100

100

n = 1.517

73.77°

0.04

0.04

0.04

0.05

0.07

0.14

0.58

6.28

100

100

n = 1.531

75.69°

0.02

0.02

0.03

0.03

0.04

0.08

0.32

2.82

100

100

n = 1.550

78.82°

0.01

0.01

0.01

0.01

0.01

0.03

0.11

0.77

100

100

n = 1.570

83.55°

0.00

0.00

0.00

0.00

0.00

0.00

0.01

0.07

1.73

100

Idiot Savant?

But back to Marilyn vos Savant. She correctly identified the solution to the Three Doors Puzzle. Didn't do her a helluva lot of good. Many accused her of being one cell short of an ameba (and some of her relatives didn't even see the column). So severe was the reader invective that she had to run the solution twice. Marilyn – take solace: Galileo had a hard time, too – it took the Catholic Church 300+ years to admit their mistake, even with God on their side.

Beliefs? I guard mine with a vengeance. I defend their virtue against interlopers one and all. But when I open Door Number Three and find them in bed with the neighbor's ten-year-old daughter, I never forget to flush. By the way, did I tell you my sister saw David Koresh in Waco three days after the attack…

 

Answer to emerald problem. E, D, B, A, C [back to text]

emerald, emerald enhancements, Opticon, gemology, oil treatment

E. = 1.500

emerald, emerald enhancements, Opticon, gemology, oil treatment

D. = 1.517

emerald, emerald enhancements, Opticon, gemology, oil treatment

B. = 1.531

emerald, emerald enhancements, Opticon, gemology, oil treatment

A. = 1.550

emerald, emerald enhancements, Opticon, gemology, oil treatment

C. = 1.570

Emeralds before (left) and after (right) fracture filling with various oils/resins. The fillers have refractive indices (RI's) of 1.500, 1.517, 1.531, 1.550 and 1.570, while the emerald's RI's range from 1.569 to 1.580. The above photo shows the images organized from farthest to closest RI match with the surrounding emerald. (Photos ©1999 Maha Tannous/GIA-Gems & Gemology; used with permission)

Acknowledgments

The author would like to thank Alice Keller, Mary Johnson and Maha Tannous of the Gemological Institute of America for generously consenting to the reproduction of the emerald photographs. Many thanks also to John Emmett and Karen Palmer of Crystal Chemistry (22721 NE 123rd Circle, Brush Prairie, WA, USA) for help with the math for my reflectivity determinations.

 

Author's Afterword

Published in GemKey Magazine (2000, Vol. 2, No. 3, March-April.), this was installment #9 of my Digital Devil column. Unfortunately, Mr. Murphy made an appearance. The editors forgot to place the photos in the proper order, meaning that the key was wrong. The above photo order is correct for the answer key as given.