Silicone tends to be a more eco-friendly option. A plus is it comes from quartz / sand , but the negative is the hydrocarbons used to make it come from petroleum or natural gas. The methods for getting the materials and processing it does have environmental critics. With that being said, silicone is much more friendly than plastic when used in the kitchen / food storage. Silicone is hardier and longer lasting. It has a lower chance of leaching chemicals into food when using for storage. It can be microwaved, used in the oven and freezer. Silicone can be a good option as long as it's maintained to ensure a long lifespan, and recycled when it can no longer be used.