Solids deposition in a gas environment, such as a gas transmission line or pipeline are measured using metal-coated quartz crystal microbalance (QCM) in a QCM probe within a high pressure gas chamber in the gas environment. The metal coated on the QCM may be iron, iron alloys and/or iron oxide. The weight measurements are conducted at a constant (ΔT) or controlled (T=f(t)) temperature between the high pressure gas chamber and the QCM probe. The weight gain during a CE cycle is associated with the solids formation rate.