My block/item texture looks like a Purple and Black block?

Please follow along with the video above. Press the button below to view the flowchart on how to fix the issue. 

NOTE: This flowchart was made for 1.8, it is still mostly accurate. The biggest difference is anything that had camel case is now snake case in newer editions. EX: "mySword" is now "my_sword"

For extra clarification on the JSON files try checking this out: