Harvey Water Softener resin is made from petrochemical products.
Resin is synthentic plastic made from polysterine sulfonate, shaped into beads that look like brown sugar. Each macroporous sulphonated polystyrene bead has a 1% DV cross linking that works to soften resins. The technology is unsurpassed to date.
Resins last a long time - the water softener is more likely to wear out before the resin. A Harvey Water Softener will not need a new resin during its normal lifetime.