Heat treating agate is a technique that has been used for thousands of years in India and the heat treating of steatite , soapstone ,was a widely used technique in the mid east thousands of years before that development. Heat treating often is a direct expression of the regional culture and as such can seem bizarre to many western stonecutters. Probably the best case of that nature would be the heat treatment of fine green New Zealand jade to get the locally much more prized inanga jade which is white. The indigenous people of New Zealand , the Maori, prized the white jade because it represented an important food stuff the fish known as white bait.The Egyptians cunningly carved steatite first then heated it to make it much harder and resistant to wear. Steatite is a fairly ugly stone so they coated the unheated but carved steatite with a glaze which we know as faience or Egyptian paste.Glazes in the mid -east are unique in that the chemistry of the rocks were quite different than in the pottery centers of Asia. The Egytians developed a glaze with which they could coat stone or ceramic and upon heating the mineral colorant would migrate to the surface.Copper blue is the classic example. Traditional eastern glazes are actually quite different being layered glass.Faience does not take fine detail so a certain simplified carving style evolved.In India the Indus valley was the production nexus of the world bead trade for many centuries. The famous Deccan trap rocks are full of agate filled vugs and very early on they learned to heat treat the agates. This had a dual purpose in that they conveniently cherished red stones and the heat treating that produced red in iron filled agate also had the effect of softening the agate a bit making the work of shaping easier.Since heat treating often only changes the very outside layer of an agate the heat treating would be repeated 5 times or more as the shaping progressed. Techniques will be discussed in future posts.