Booksellers value rare books according to past auction prices, condition, inscriptions (or lack thereof), edition and even issues within editions.

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It's rare enough to have intrinsic value but sufficient enough to be traded in the mass, global market.

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Another is success: high-value targets have become rare.

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Largely mined in China, rare earths have been shooting up in value as increasing amounts are used around the world.

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Gold is that very rare thing--it has intrinsic value, but enough of it exists to support an adequate volume of trading in it.

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This past week several such funds also saw their shares fall below the intrinsic value of their bullion holdings, a rare event.

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But such oscillations in the value of the yuan against the dollar are rare.

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Instead, you have to move your money first to, say, a stock fund, for 90 days or so. (Cash withdrawals have no waiting periods.) And in the rare case that your employer ends its participation in a stable value fund, your money might be held for up to 12 months (still earning a return) as the fund unwinds.

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Some assets, such as timber, may have a market value, but that value does not encompass the trees' role in harbouring rare beetles, say, or their sheer beauty.

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With a slew of old, rare and fine wine widely available, as well as many different kinds of good-value wines on offer, you may wonder why bother at all.

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