please help me understand whar my rocks are made of

[plank]

Hello everyone,

 

I found some rocks in my childhood, kept them for 20 years and now I need to know what they are made of (in case they would harm my gecko),

 

Any gess of what if could be ? or maybe experiments to help (vinager, magnet, ..) ?

 

1. bleu, purple, gold, white(solid) 

2. dark brown, verry spongious volcanic like

3. black melted like shape, dark gold like depot 

4. Iron like, melted shape with cracks

 

link to rocks images : https://postimg.cc/gallery/B0W35Jq

(I can provide more photo if needed)

 

Thank you for your help !