No it's not.
The Blue Lead is in California. The Blue Lead has been traced from Little Grizzly, about latitude thirty-nine degrees and forty-five minutes, in Sierra County to Foresthill about latitude thirty-eight degrees, fifty-five minutes, in Placer county, a distance of sixty-five miles. The course is south-south-east, the position about thirty miles west of, and parallel with, the main divide of the Sierra Nevada. The elevation is five thousand feet above the sea at Little Grizzly, and two thousand eight hundred at Forest Hill, showing an average fall of thirty-three feet per mile.
Blue clay can be an indicator of several minerals - the most commercially valuable of which is silver. The Blue Lead was a single channel in California. The color blue was an indicator in that tertiary deposit. There may be other blue minerals associated with gold deposits but they are not the Blue Lead.
Here in the desert southwest we have huge amounts of heavy black sand deposits. Although black sands are often found in association with placer gold the black sand is not an indicator mineral. The vast majority of black sand deposits have no gold at all.
In all mineralized areas quartz is common. Although quartz is often found in association with placer gold quartz is not an indicator mineral. The vast majority of quartz deposits have no gold at all.
In some gravel deposits you may find blue clay. Although blue clay is sometimes found in association with placer gold blue clay is not an indicator mineral. The vast majority of blue clay deposits have no gold at all.
The best indicator of gold for the placer miner is the presence of recoverable gold. It's the simplest metal to check for the presence of and luckily the test procedures are identical to the recovery procedure. Gold is
the indicator mineral for placer deposits.
Once you get an intimate knowledge of the mineral associations found with any specific gold placer you may be able to make some assumptions about the relationships of those minerals to gold deposition
in that one deposit. The Blue Lead was a clay association found in one specific deposit in California.
Gold is where you find it.
Heavy Pans