Help with gravels and indicators

[leeleelee]

Note: Thread posted by RoughCreations on behalf of forum member: leeleelee - originally posted just as a Gallery picture:
Hi,
I'm very new to all of this and have been digging around a creek with gravels like this. Haven't found any spinel or anything heavy so I'm not sure if I'm looking in the wrong spots or maybe just nothing like that in the area. This area is only about 50kms of locations known for sapphires and rubies. Im just wondering if anyone can tell from looking at these pics if this types of wash would be an indicator of anything of interest?
TIA

[Faceting Frank]

This looks like the top layer of river gravel, which is mostly quartz. You need to fossick in creeks that are known to have sapphires and get to the bottom layer of gravel.

[RoughCreations]

This looks like the top layer of river gravel, which is mostly quartz. You need to fossick in creeks that are known to have sapphires and get to the bottom layer of gravel.

Agree.
I made this same mistake in NE Tas early on when fossicking for sapphires with the family. I knew the theory, but it didn't sink in initially. Basically, you have to dig a hole straight down in an area of gravels, ignoring the overlying material until you hit bedrock. If the bedrock has some cracks, grooves or natural traps for high density minerals, all the better - focus on these features and start your sieving here. All going well this base layer (at least in Tas) has black spinel (lion's share), topaz, zircon, (gold, osmiridium) and maybe even some sapphire.
RC

[MrSydney]

Rough Creations largely has it.
Sapphire, Zircons etc are 'heavy' so fall to areas where gold would.  So looking in cracks etc but also look for spots in your creek / river behind larger rocks where the water flow is interrupted and swirls behind it as heavier stones like sapphire 'drop' in these areas.  Also anywhere there are little 'waterfalls' (not big ones, anywhere the water drops off a bit even if only 5 - 10cm say) right up against where the water drops over.  There are some good youtube video's by Liz Kreate and others that talk about this - just search 'YouTube Liz Kreate sapphires'.