Field Trip

USE OF COLOR IN MINERAL IDENTIFICATION

In some minerals color is directly related to a metallic element, is characteristic, and can be useful in identification. As examples,  azurite as shown in Figure 1A, is always blue due to the presence of copper, and rhodochrosite, shown in Figure 1B, is always pink to red due to the presence of manganese,. However minerals such as fluorite, colorless in it self, can be yellow, blue, purple, or green due to low concentrations of metal impurities.

USES OF CLEAVAGE, PARTING, AND FRACTURE IN MINERAL IDENTIFICATION

Cleavage in a mineral is the tendency for the crystal to split along definite  crystallographic planes as exemplified by the rhombohedron cleaved from a calcite crystal shown in Figure 1[Ref1]. These planes of weakness are present within a regular repeating array of atoms and ions within the crystal and are always parallel to a potential face of the crystal.

Meteorites

Meteorites are stuff from outer space; each is a solid piece of debris which formed from dust within the protoplanetary disc or from object such as an asteroid, planetesimal, or […]

Art Deco Rubies

Art Deco is my favorite style of jewelry, with its flair of design and the use of unusual combinations of gemstones. Art Deco is a style of architecture and design […]

Largest Star Sapphire/Ruby

We usually think of star sapphires and rubies as stones in the few carat range, not in hundreds and thousands of carats. But some are an amazing size. At the […]

Corundum – From Sapphires to Rubies

Gemstones of the mineral corundum [Ref 1] offer a rainbow of colors for the lapidarist and jewelry maker as displayed in Figure 1.  Traditionally, of these, the ruby and blue […]

Fluorite, A Gallery of Specimens

I’ve assembled a gallery of 15 fluorite specimens from some of the locations around the world which are favored by collectors.