Tourmalines have a very complex chemical composition, and more than a dozen mineral species are recognized within this group.

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

化学的に純粋なベリルは無色ですが、微量元素によって緑、青、ピンク／赤の色になります。

Although colorless when chemically pure, zircon is typically yellow-brown to brown. It also comes in red, blue, purple, and green. Because of its high brilliance and dispersion, colorless zircon has sometimes been used as a substitute for diamond in jewelry.

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

Mr. Sevdermish(セブデルミッッシュ)氏はとりわけ, タンザニア産宝石が持つ素敵な色の範囲（天然および若干加工済みのもの両方）に熱い情熱を向けられます。

This document provides guidelines for submitting manuscripts for publication to the Gems & Gemology journal.

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

Found in nearly every color – most notably red, pink and blue – spinels are popular gemstones because of their abundance, moderate cost and attractiveness.

Often thought of as a deep red gemstone, garnet can also be yellow, orange, green or brown – any color except blue.