Fact 1: Vein deposits of gold and silver are formed by igneous intrusion.

Fact 2: Jewelry is made of silver, gold or platinum and is usually set with precious stones.

Given the two facts above, answer the question "What geological formation must occur for the availability of material for silver jewelry to occur?" with the following options: 
- Igneous intrusion
 - Metamorphic Layers
 - loose soil
 - tectonic plates coliding
 - Physical weathering
 - Volcanic mountains
 - permineralization
 - Sedimentary deposits


 

 Igneous intrusion        