A heat exchanger (10) comprises a glass body (20) having a first flat face (40) and a second flat face (50) on opposing ends, and defining a longitudinal axis (A) therebetween. A plurality of holes (70) in the glass body are elongated along the longitudinal axis (A) by extending from said first flat face (40) to said second flat face (50). The plurality of holes (70) are configured to receive and direct a gas therethrough, to exchange heat between the gas and the glass body (20).
