Randy is right. For a VLF, a DD over and rather than Concentric(Mono) for higher mineralization IS more important than frequency. But that said a lower frequency will handle mineralization better than higher frequencies.
Inhere wrote, "Out here the high freq setting on the (Minelab XT) 18000 is just about a passenger, useless in the hot ground, did you try this setting with the eureka?"
Steve Herschbach, "But the Eureka Gold cannot handle the hot rocks at Moore Creek. The only way I could get it to shut up was to go to the 6.4 kHz mode, but the gold sensitivity in that mode sucks."
http://www.nuggethunting.com/forums/index.php?showtopic=6087
Also Tortoise, I know this is not a PI forum but look below. I always thought the Goldquest is a beach machine and not meant for nugget hunting, as it is made by the same company as the Goldscan 5B. I also thought I would rather buy a Infinium instead of a Goldquest but maybe the Goldquest is good for gold nuggets too??
"It is equally at home on a wet or dry beach or in mineralized areas where gold nuggets are to be found." and "GOLDQUEST SS V.3 is the most sensitive treasure hunting PI on the market today . It easily detects low conductivity jewelry, thin gold and platinum rings and nuggets of less than 1gm in weight."
http://www.surfscanner.com/Surfscan3/Qoldquest1.html