The jar is heavier than I expected, it is made from black glass. The color is part of the glass and not painted on, it blocks light very well. The cap is aluminum, as far as I can determine. It seals well and includes 5 storage bags. I have a dog with a very good sense of smell so I used him to check this product. He can sniff out his dog treats no matter what I put them in. Not with this. Good product and well made, performs as advertised.