||is a green ore of copper. It is related to:
|| which is deep blue, is also an ore of copper. Azurite was used by
some of the Old Masters as a blue pigment for oil paintings.
|Lapis (Lapis lazuli)
||is a blue semi-precious form of the mineral Lazurite (Sodalite
mineral group). Its formula varies and is quite complex; but basically it is a sodium-calcium
silicate with varying amounts of sulfur, sulfate, chlorine, and water (hydroxyl).
|| is a well known blue-green semiprecious stone.
|| is also blue-green, but has less blue than turquoise.
|Coral, Mainly CaCO3
|| is reddish pink. It is illegal to harvest live red coral (a conser- vation measure that
I strongly endorse). My coral comes from Bali, where a deposit of fossil (long dead) coral has been found.
|Abalone Shell (CaCO3)
||Is simply crushed pieces of the shell of the abalone mollusk. It has
a "mother-of-pearl" iridescence.
||Is not a mineral but rather a very fine-grained hematite-cemented siltstone.
|Natural- and Shaped-Edge Pieces
|Sometimes I turn pieces that still retain the bark - or, when the
bark has come loose and flies off, the shape of the wood just under the bark. These are referred to
as "natural-edge" and "shaped-edge" objects. Some folks like them for their rustic appearance and
irregular outlines. In virtually all cases they are much more challenging to make, as the lathe
tools are "cutting air" for a portion of each revolution of the lathe. They take more time, and the
failure rate is higher. Thus for an object of a given size, natural-edge and shaped-edge pieces are
A recent addition to the collection is double-natural-edge bowls, where the original wood
edge is retained on both the top and bottom! The editor of "Woodturning Design" magazine says
that he has never seen this style before; evidently it is unique to The Well Turned Bowl. I have
described the process of making double-natural-edge bowls in the newsletter More Woodturning (Vol. 11,
#5, p. 11-15, June, 2006)
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