Category: Gem Notes

Cerussite

Cerussite is a mineral species, lead carbonate, with the formula PbCO3. It crystallizes in the orthorhombic system. It is an important ore of lead.

Phenakite

Of all the colorless “rare gems,” phenakite is perhaps the most desirable of almost all of its colorless counterparts for several reasons.

Pink Diaspore

Much of the pink diaspore rough seen to date has areas capable of cutting medium to large size stones that are eye clean and in many cases loupe clean

Scapolite – Fluorescence

I first reported on scapolite as a rare stone becoming part of the jewelry landscape back in the September/October 2009 issue (Volume 28, Issue 5). The mineralogical prop- erties are being repeated below for reference. (Ed. Note: subscribers can log in to the website, go to News and Cur- rent Publication, and search on the archives—Scapolite— to find this article in entirety.)

Blue Sapphire with Fluorescence

Fluorescence is a common feature for a gemologist to note for a variety of gem materials. Some common gems of which fluorescence is well-known include diamond, ruby, pink spinel, pink and purple sapphire and alexandrite.

Scheelite

Scheelite is a mineral species, calcium tungstate, with the formula CaWO4. It is an important ore of tungsten that gained value during the 20th century for use in filaments in light bulbs and as an alloy in steel.

Cuprite

INTRODUCTION Cuprite is a mineral species, cuprous oxide, with the formula Cu2O. It was named in 1845 by Wilhelm Karl von Haidinger. The name comes from the Latin “cuprum” in allusion to its composition. Cuprite is…

Vayrynenite

In the course of my 40+ year career in gemology, many gemstones have crossed my desk but rarely are they so special that they take your breath away. In the last year, this happened twice. The first time was with a 24 ct unheated padparadscha sapphire in a private collection.

Rhodonite

INTRODUCTION Rhodonite is a mineral species, manganese inosilicate, with the formula MnSiO3. It often contains minor Ca and traces of Mg and Fe. The name rhodonite comes from the Greek for “rose” (rhodos), in allusion to…