Nephrite Nephrite Nephrite is a variety of the calcium, magnesium, and iron-rich amphibole minerals tremolite or actinolite (aggregates of which also make up one form of asbestos). The chemical formula for nephrite is Ca(Mg, Fe)SiO(OH). It is one of two different mineral species called jade. The other mineral species known as jade is jadeite, which is a variety of pyroxene. While nephrite jade possesses mainly grays and greens (and occasionally yellows, browns or whites), jadeite jade, which is rarer, can also contain blacks, reds, pinks and violets. Nephrite jade is an ornamental stone used in carvings, beads, or cabochon cut gemstones.
Ornamental turning intervals around the work (so producing grooves or bumps on the surface) to non-circular movements whereby the whole of the circular shape is removed to give a completely different form. Such shapes are achieved by various means, the principal ones being: Ornamental turning is believed to have originated in Bavaria in the latter part of the 15th century when it consisted mostly of rose-work, being done by using a cam or template (called a rosette) mounted on the lathe spindle and allowing the headstock to rock under tension of a spring or weight, to follow the contour on the edge