his being the case a cut topaz is very likely to be damaged by a blow
or even by being dropped on a hard surface, and it would be wiser not to
set such a stone in a ring unless it was to be but little used, or used
by one who would not engage in rough work while wearing it. Thus a lady
might wear a topaz ring on dress occasions for a long time without
damaging it, but it would not do for a machinist to wear one in a ring.

GEMS BETWEEN 7 AND 8 IN HARDNESS. We now come to a rather long list of
gem minerals ranging between 7 and 8 in hardness. Of these the principal
ones are zircon, almandine garnet, and beryl (emerald and aquamarine)
rated as 7-1/2 in hardness, and pyrope and hessonite garnet rated as
7-1/4 in hardness. Tourmaline and kunzite may also be included in this
group as being on the average slightly above 7 in hardness.

The above minerals are all harder than quartz, and hence not subject to
abrasion by the quartz dust which is everywhere present. In this respect
they are suitable for fairly hard wear. The garnets are of sufficient
toughness so that they may be freely used in rings--and the extensive
use of thin slices of garnet to top doublets proves the suitability of
the material for resisting wear. The zircon is rather more brittle and
the artificially whitened zircons (known as jargoons) are especially
subject to breakage when worn in rings. Fortunately jargoons are not
commonly sold.

The beryl, whether emerald or aquamarine, is rather brittle. Emeralds
are seldom found in river gravels. The material cannot persist in the
mountain streams that bring down other and tougher minerals. The extreme
beauty and value of the emerald has led to its use in the finest
jewels, and the temptation is strong to set it in rings, especially in
rings for ladies. If such rings are worn with the care that valuable
jewels should receive they will probably last a long time without any
more serious damage than the dulling of the sharp edges of the facets
around the table. This slight damage can at any time be repaired by a
light repolishing of the affected facets. If an emerald is already badly
shattered, or as it is called "mossy" in character, it will not be wise
to set it in a ring, as a slight shock might complete its fracture. What
has been said about emerald applies equally to aquamarine except that
the value at stake is much less and the material is usually much freer
from cracks.

Tourmalines, like emeralds, are brit