It all began on a January afternoon in 1848, when a carpenter named James Marshall found gold in the tailrace of John Sutter's mill near the junction of the American and Sacramento rivers. One of Marshall's workmen recorded in his diary that night, 'This day some kind of mettle was found in the tail race that looks like gold, first discovered by James Martial, the Boss of the Mill'. In fact, Marshall was not at all sure that it was gold, so he hurried back to Sutter's house to consult the Encyclopedia Americana. The description of gold so convinced him that he went rushing back to the mill in pouring rain and missed his supper. At first, Marshall and Sutter tried to keep news of the discovery quiet, but rumours of gold were not easy to quench. Soon the word had spread to San Francisco - then a struggling port of about 2,000 people. By spring, half of California had deserted its farms and homesteads to rush to the gold fields. 'The whole country from San Francisco to Los Angeles and from the seashore to the base of the Sierra Nevada resounds with the sordid cry of gold, GOLD, GOLD!,' reported the San Francisco Californian in May 1848. 'The field is left half planted, the house half built, and everything neglected but the manufacture of shovels and pickaxes.'

The gold seekers were hardly disappointed. They found not only the sandbars and banks of the rivers near Sutter's Mill rich in alluvial gold, but were also quickly able to trace deposits in other streams coming down from the Western slopes of the High Sierras. Throughout that first summer, the Californians had their find almost exclusively to themselves, for in the days before the telephone or cable the news of the discoveries percolated slowly even to the eastern seaboard of the United States.

To most Americans, California was still a remote, uncivilized strip of land that the United States was in the process of acquiring from Mexico, along with New Mexico, for $15 million. But what happened was unprecedented. Thousands of men suddenly saw a spark of opportunity to earn a fortune. 'It is well and truly said,' wrote a New York correspondent reporting to the Banker's Magazine in London, 'that the shoemaker is throwing away his last, the tailor his bodkin, the mason his trowel, the labourer his hod, the carpenter his chisel, the printer his stick, the painter his rush, the farmer his harrow, the quack his nostrums, the baker is leaving his dough, the butcher his stall, the clerk his desk and even the loafer his roost.'

There were three routes to California: by ship around Cape Horn; by ship to Panama, then across the isthmus on a donkey and by ship on to San Francisco; or, finally, the long haul overland across the plains and through the mountains and deserts to the coast.

The thousands who rushed to California from all over the United States found Englishmen, Frenchmen, and even the Chinese hard on their heels. This was an international gold rush. By mid-1849, one Scotsman was writing home to his family in Edinburgh, 'This is the seventh week I have been here: we have averaged from 18 to 32 dollars every day this week … as far as I can judge those who work steadily can make from 12 to 30 dollars per day. Cases are occurring of some getting from 100 to 200 dollars per day'. By the end of 1849, there were at least 40,000 men working in the gold fields and they scoured out $10 million worth of gold.

Few knew anything about mining, but they quickly learned what telltale signs to look for amid the sand and gravel in the bed of a creek, and how to pan. It was essentially a simple process. The miner filled his pan with gravel and picked out the large stones by hand, then rotated the pan between his hands to keep the contents suspended in the water. One side of the pan was tilted slightly higher than the other so that the water carried away the light particles, while the heavier particles of gold were left as a residue. As the search for gold became more sophisticated, the primitive panning process was supplemented by a 'cradle' - a long wooden box on rockers - which enabled much larger quantities of gravel to be handled at a time.

From the original find at Sutter's Mill, the miners ranged out along the Sacramento river and traced the gold back into the Sierras. There the prospectors soon located a belt of gold-bearing rock over 100 miles long and varying in width from a few hundred feet to 2 miles. They called in the Mother Lode, for it was from this quartz rock that the gold had been scoured over the centuries and washed down the rivers. The mining camps sprang up overnight wherever a promising new find was located. The prospectors lived in leaky tents, lean-tos or log cabins. It was a hard, often unrewarding, existence. They toiled all day beneath the hot Californian sun, up to their waists in water. At night they went back to their huts to eat whatever food might be available and to soak up bad whisky. The census of 1850 showed that 92.5 per cent of the population was male. Most of the females were girls working in the saloons amid long gilt mirrors and red calico curtains.

Throughout it all, the gold production increased year by year to 77 tonnes (2.5 million ounces) in 1851, then a peak of 93 tonnes (3 million ounces) in 1853. The US Mint began coining Californian gold in such profusion that silver coins became scarce almost overnight. Yet the Californian rush had a relatively short life. The alluvial gold that was easily available on the surface was quickly scooped up. Once it had gone, the search for gold called for more patience and better equipment. By the mid-1850s, the pattern of gold mining was changing. No longer was it the individual miner with his pan, but a group of men joining together and pooling their capital to build more elaborate crushing equipment and to dig deeper. As early as 1851 the San Francisco weekly Alta California noted, 'We have now the river bottoms and the quartz veins, but to get the gold from them we must employ gold'.

Miners still dashed off at the least hint of gold. There was a rush to the Fraser river in British Columbia in 1858; Pike's Peak, Colorado in 1859; and Boise, Idaho in 1862. None of them produced gold on any scale comparable to California. The richest discovery was the Comstock Lode near Virginia City, Nevada, in 1859. The Lode contained such high-grade deposits of gold and silver that, ultimately, it yielded $306 million worth of the two metals, including 193 tonnes (6.2 million ounces) of gold. Among those in Virginia City at the height of the rush was Mark Twain. He later wrote about the boom town in Roughing It: 'Money was as plentiful as dust: every individual considered himself wealthy, and a melancholy countenance was nowhere to be seen. The "city" of Virginia … claimed a population of fifteen to eighteen thousand, and all day long half of this little army swarmed the streets like bees and the other half swarmed among the drifts and tunnels of the "Comstock", hundreds of feet down in the earth directly under those same streets. Often we felt our chairs jar, and heard the faint boom of a blast down in the bowels of the earth under the office'.