How much spice was in the Atreides' lost harvester?

Question

Duke Leto Atreides commanded fierce loyalty from his subjects, a large part of which comes from his reciprocal loyalty to them, and this is neatly portrayed in the book:

• Leto, Paul, Liet-Kynes and co. fly an ornithopter to a spice harvester in the field
• It is attacked by a worm
• Rather than accept the loss or attempt to salvage spice, Leto (unexpectedly) ordered an impromptu rescue operation, saving the entire harvester crew, but losing a full load of unrefined spice

This action went a large way towards winning the allegiance of the xenophobic Fremen.

It is heavily implied that this was a highly unusual noble act, due to the high amount and cost of spice lost. How much value was lost, exactly? We know that "one briefcase full of spice would be enough to purchase an entire planet", but in this case:

• The spice was unrefined
• The amount was a full harvester load

How much, approximately, would this estimate to be?

Answer 1

We can do some "back of the envelope" calculations based on Leto's conversations with Hawat. Note that these figures are very rough and contain a considerable number of assumptions:

“They neglect to mention that less than half the crawlers are operable, that only about a third have carryalls to fly them to spice sands—that everything the Harkonnens left us is ready to break down and fall apart. We’ll be lucky to get half the equipment into operation and luckier yet if a fourth of it’s still working six months from now.”

“Pretty much as we expected,” Leto said. “What’s the firm estimate on basic equipment?” Hawat glanced at his folder. “About nine hundred and thirty harvester-factories that can be sent out in a few days. About sixty-two hundred and fifty ornithopters for survey, scouting, and weather observation … carryalls, a little under a thousand.”

and

The Duke turned to Hawat. “Thufir, did you get those account books you said you could buy?”
“Yes, my Lord. They’re being examined in detail even now. I’ve skimmed them, though, and can give a first approximation.”
“Give it, then.”
“The Harkonnens took ten billion solaris out of here every three hundred and thirty Standard days.”

So, with about 1500(ish) operable spice harvesters, the Harkonnen were able to extract around 6.6M Solaris per annum per harvester. A single load seems to take a day or so to harvest and let's say a day on either side for repair and recovery so each harvester can make maybe 100 trips a year. That means that each single load equals approximately 60,000 Solaris. and that, assuming it takes a year to replace, results in a total loss to the business of over 6,000,000 Solaris as well as the value of the harvester itself (h/t to @friggle for pointing this out).

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But we can go further....

Since we know that the price of spice can be as much as...

620,000 solaris the decagram.

...we can estimate that a full harvest load might contain as many as 10 grams of refined spice.

As the average suitcase can hold 20000 grams, you'd need some 2000 trips to fill one.

Since the 1500 harvesters can make approximately 150,000 trips per annum, that means that a suitcase of spice (with which one could purchase a planet) is worth around 10-15M solaris or roughly twice the average annual output of a single harvester.

Answer 2

While we can still calculate out the value of the spice lost with the harvester, the significance of this event was not directly the value of the lost spice. It was the value of the harvester.

The spice itself was not salvageable. The only way to save any spice was to save the harvester. Richard's answer has done an amazing job of calculating out the value of the spice load itself, but the real loss here is 1/934th of his total annual output.

It's a bit of a hair-splitting distinction to make, but consider that neither the Duke Atreides or Baron Harkonnen could have saved the spiceload if they wanted to. The obvious difference is of course that the Duke put his life in danger to save a few anonymous workers, but what really sticks with Kynes is how the Duke remains angry about that danger, and never cares about the value of the lost crawler.

And Kynes, returning the stare, found himself troubled by a fact he had observed here: This Duke was concerned more over the men that he was over the spice. He risked his own life and that of his son to save the men. He passed off the loss of a spice crawler with a gesture. The threat to men's lives had him in a rage. A leader such as that would command fanatic loyalty. He would be difficult to defeat.

This event doesn't directly impact Fremen allegiance. The Duke wasn't alive on Arrakis long enough for the Fremen to ally with him. This passage mainly foreshadows how Paul later creates fanatic loyalty of his own.

It does change Kynes' personal opinion however. There are several moments during this trip where Paul reminds him of the legend of Lisan al-Gaib (the stillsuit fitting, identifying the Fremen who were onboard the crawler). Jessica notes that evening he was cold to the Atreides prior to this trip, and is no longer.

Later that night, after the Sardaukar attack, Kynes helps Paul and Jessica escape into the desert. During this, he has several moments of doubt. He has his own goals (transforming Arrakis), and he could advance his agenda by selling them out. If not for the harvester incident, he would had no reason to not sell them out. Immediately after he helps them escape, he is captured by the Harkonnens and dies.