It's nice to see my concept has yielded some positive feedback. I uploaded the resource pack for those who are interested. You'll need MCPatcher if you want it to work properly though.
Admittedly, Venus is quite tricky when it comes to depiction. The only actual surface pictures of Venus in existence are a result of the Soviet Venera program back in the 70ths and 80ths.
View attachment 514
Some kind of volcanic deposit. It got to have some kind of use, right? There's also a volcano in the background, but it might be hard to see if you got a crappy monitor (like me). I'm still not certain about the sky, but it appears it's yellow during noon, but turns amber toward dusk.
The fog in the picture has also been manipulated by merging multiple images with different draw distances. Basically, it makes the fog start earlier, which makes it much more stretched out than the default fog.
I'm not sure about Venusian features. It does have sulfuric acid rains, but the heat will vaporize it before reaching the surface. However, a metallic counterpart to snow has been identified on the Venusian mountains. It's speculated to be lead sulfide, but in Galacticraft it could just be called something like 'Venusian Snow' instead.
Perhaps there could also be some kind of semi-solidified lava blocks that turns into lava when broken? Its logic is comparable to ice.
A suit on Venus would be required to withstand both extreme heat and pressure, so logically it could be some combination between an atmospheric diving suit and an entry suit. Not sure what material it would be constructed of, but I guess the possibly Mars exclusive desh ore could be one ingredient.