Growing numbers of investing experts have been declaring that gold is a bubble: an insanely overvalued asset whose price is bound to burst.

There is no basis for that opinion. And understanding why can help point an investor toward clearer thinking about frenzied markets.

Sure, gold seems expensive. At its recent price of $1,813 an ounce, gold is off only slightly from the record high of $1,912 touched on Sept. 6 (unadjusted for inflation). Gold is up more than 40% over the past year, largely on fears that paper currencies like the dollar won't retain their value.

But that doesn't mean it is overvalued. Unlike bonds, which provide interest income, and stocks, which produce dividends and earnings growth, gold generates no cash flows. As John C. Bogle, founder of the Vanguard funds, told me two weeks ago, gold "has no internal rate of return." As a result, there isn't any reliable way to tell what it is worth.

So the people who say gold is in a bubble might well be right. But the people who think gold is heading for $2,500, $5,000 or $10,000 also might be right

Folks on both sides would be more intellectually honest if they admitted that they are just guessing what gold is worth. With no measures like price/earnings ratios or bond yields as benchmarks of value, figuring out whether the precious metal is cheap or dear is like trying to solve a Rubik's cube while you are blindfolded.

Decades ago, the great investing analyst Benjamin Graham pointed out that there is no such thing as a "good" stock; every company is good at one price (when it is cheap) and bad at a higher price (when it is too expensive). But try asking a gold bug at what price he would sell, and you are likely to get an answer somewhere between $6,000 and "never." Ask a gold skeptic at what price he would buy, and you be met with silence, followed by "never" or a quavering "$900, maybe?"

Precisely because I don't know how to determine its fundamental value and have never been able to identify anyone else who can, I haven't written about gold for years.

But there is one aspect of gold investing where it is possible to make rational estimates of value: the stocks of gold-mining companies. And, by historical standards, they seem cheap—based not on subjective forecasts of continuing fiscal apocalypse, but on objective measures of stock-market valuation.

越来越多的投资专家断言黄金已经成为一个泡沫，他的价值被高估而且这个泡沫必定会破裂。

确实就、黄金看似昂贵，在他在最近达到$1813枚盎司的时候，他的价格才比在9月6日达到的历史最高水平$1,912枚盎司稍稍降低了一点。在过去的一年里，黄金价格上涨超过了40%，这很大程度上依赖于对于比如像美元一类的纸币贬值的恐惧造成的。

但是这并不意味着黄金价格被高估了，不详提供利息收入的债券，也不像        。黄金不生成任何现金流。就如Vanguard funds的创始人John C. Bogle在两周前告诉我的黄金没有永久的回报率，因此没有什么可信的方法去断定他的价值到底是多少。

因此那些声称黄金是泡沫的人可能是正确的，而那些认为黄金价格会达到$2,500, $5,000甚至$10,000的人也可能是正确的

如果这两方面的人承认他们只是在猜测黄金的价格的话，他们就会显得比较诚实。因为没有计量价格的方法比如利率和债券收益。猜测贵金属价格是否便宜或者昂贵就像是在猜测

许多年前，伟大的投资分析专家Benjamin Graham指出，从来就没有一个所谓好的股票市场，任何一家公司都回在某个价格上收益（当价格低的时候），也可能在某个价格上亏损（大包当价格高的时候），但是尝试询问一个黄金迷它会在那个价位出售黄金，你有可能得到的价格是$6,000或者永远都不卖。当你询问一个黄金怀疑者的话，在什么价位它会买入黄金的话，你可能会得到永远都不买或者可能是$900巴，然后就是无尽的沉默

因为我不能准确地断定黄金的基本价格，亦不能判断有人可以去断定，所以我在多年之内都没有写关于黄金的文章

但是在黄金投资的一个领域我们可能会对黄金的价格作出合理的判断。这就是gold-mining companies期货市场