Jewelry is worn and enjoyed for its beauty, and eventually passed down from one generation to the next. Here, discussion focuses on the quality of the materials used in jewelry, from the viewpoints of the nature of the beauty in gemstones as they are being worn, and their quality at the time they pass from one person to the next.

The hardness and durability of gemstones differ between gemstone types, Diamond has a Mohs hardness of 10, while ruby and sapphire are 9 and emerald is 7 1/2 to 8. Quartz, the most abundant mineral in the earth’s crust, has a hardness of 7, and is a major component of dust. This is important, because anything softer than dust is subject to wear and tear, However, it is not uncommon to come across rubies with facets that are severely worn. Even a diamond that has been worn for many years in a ring may become chipped around the girdle, making re-polishing necessary before resale. Gemstones with hardness and durability that are less than adequate are best used in jewelry other than rings, such as brooches or pendants.

Even among gemstones of the same variety, beauty and other characteristics may be totally different depending on country of origin, In contrast to the soft red character of the color of Mogok rubies, most rubies from Sri Lanka have a highly transparent pink character and are polished with small facets to show a unique beauty. Each major gemstone species has at least three to ten major sources. Insofar as one is wearing an expensive item, it is nice to enjoy a gemstone with the knowledge of what its country of origin is.

Currently, gemstones that generally go untreated include diamond, alexandrite, amethyst, cat’s-eye chrysoberyl, moonstone, opal, peridot, rhodolite, spinel, imperial topaz, and tsavorite. Though ruby, sapphire, and emerald are generally treated, some og these are available in untreated qualities. Gemstone treatments dramatically increase the supply for beautiful material. Especially in gem qualities, it is necessary to distinguish between treated and untreated gemstones and to properly disclose that information. In particular, emeralds that have had fractures filled with oils or polymers may change over time, so caution is necessary. Furthermore, practically all of the blue topaz available on the market is irradiation-treated.

The determining factors of beauty are different for each specific type of gemstone. The stone scintillation of a diamond, the gentle color of a Mogok ruby, the balance of the prominent mosaic pattern seen in a peridot- each exhibits its own distinctive beauty.

Note: The diagrams on these pages can be copied at actual size onto transparent sheets and used to estimate the carat weight of gemstones(30%).
Diamond S.G.=3.52
Ruby & Sapphire S.G.=4.00
Amethyst S.G.=2.65