Charles Sheffield - The Diamond Drill

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2024-11-24 0 0 5.76KB 2 页 5.9玖币
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The Diamond Drill
by Charles Sheffield
“If it looks like a duck and quacks like a duck....” But how many tests are enough?
I doubt if there is a human being alive who said, as a small child, “What I want to be when I grow up
is a tax inspector.”
That includes the Customs official (Customs are just another form of taxation) who had just pulled me
out of line with a discreet, “If you wouldn't mind, sir.”
“What's the problem?” I had been headed for the NOTHING TO DECLARE exit.
“Your luggage. You are Dr. Purcell, arriving from Pavonis Six?”
“I am.” I read his badge. “What can I do for you, Mr. Warren?”
“Are you aware, sir, that the import to Earth of diamonds, alien artifacts, and life-forms from Pavonis
Six is strictly forbidden?”
“I did know that, yes.”
“Then what about these, sir?”
We had entered an official chamber off the main entrance corridor. There, open on a table, lay my
suitcase. Beside it sat a large leather pouch, also opened to reveal a bright glitter from within.
I laughed. “Oh, I see why you are worried.” I put my hand into the pouch and pulled out a handful of
faceted stones that seemed to catch and refract every ray of light in the room. “These are stage jewelry,
Mr. Warren. They look much like diamonds, but they're not. I picked them up very cheaply, practically
for nothing. If you like, I can show you the receipt.”
“I think, Dr. Purcell, that we would rather obtain our own assurances as to their nature.” He stared at
me, but my easy confidence must have somewhat persuaded him of my innocence, because his voice was
more friendly when he said, “I presume you would not object to our conducting our own
tests-nondestructive ones, of course.”
“Not at all.” I quickly poured the handful of stones that I was holding back into the pouch and held it
out. “I hope this won't take too long-I do have appointments.”
“It will be very quick, sir, just a few minutes. We now have a fully automated procedure.” He said
that with a slight air of pride.
“A machine?”
“That is correct. This machine.” He walked across to a compact unit maybe half a meter on a side.
“It is designed specifically to establish if a stone is a diamond, or some other material.”
He emptied the pouch into a hopper on the top, and the stones vanished into the interior.
“Fascinating.” I leaned against the table. “If it's not some sort of trade secret, I wonder if you would
mind telling me how it works.”
“Not at all.” From his tone I could tell that he was delighted to talk about his department's latest toy.
“How much do you know about diamonds, sir?”
“Enough to know you can't buy them for the price I paid for those stones. Oh, and if it will scratch
glass, it's a diamond. Right?”
“Actually, sir, that's wrong. Diamonds are the hardest things found in nature, but many other
gemstones, such as rubies and sapphires and topazes, plus many manmade materials, will scratch glass.
You would be safer to state it the other way round: If it won't scratch glass, it's not a real diamond.”
“So I know even less about diamonds than I thought. This machine tests hardness?”
“It does. It also tests for density. Diamonds have a density of about 3.5 times that of water.
Zircons-a very common ‘fake diamond'-are much denser, at 4.6 and 4.7. So are rubies and sapphires at
about 4.1. Glasses are much less dense.” “I suppose the machine tests everything for densities?”
“Indeed it does. But that's not all-colorless topazes have almost exactly the same density as
diamonds, so we have to consider still another test: of refractive index.”
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分类：外语学习 价格：5.9玖币 属性：2 页 大小：5.76KB 格式：PDF 时间：2024-11-24

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