Glass Jars are generally made of soda lime glass, although jars made by Chemglass and Corning (specifically for laboratory use) are typically borosilicate Type I glass instead. Jars have straight, vertical walls and may or may not have shoulders. Straight side jars have the same size opening as their body diameter, making them ideal for maximum sample removal. Other jars have shoulders and a narrower mouth. Glass jars are inert and perfect for laboratory samples, cosmetics, candles, and air-tight storage of just about anything.