Vesuvianite (Idocrase) Mineral

This is rare purple vesuvianite (idocrase) mineral specimen material that comes from the Mamatwan Manganese Mine near Kuruman/Hotazel in South Africa.  There is about 10% Bustamite mixed in the rock which is a pretty salmon color.  Twenty (20) to thirty (30) percent speckly black manganese is mixed uniformly throughout the purple vesuvianite.  This material is rare and has only been coming out since around February 2004, mostly in small quantities with the occasional larger pocket.  Vesuvianite is not normally purple in color, making this material an excellent rock collector's item.  We verified the chemical composition of this material with Fiberquant Analytical Services in September 2005.

We are selling this material primarily as mineral specimen quality.  However, the experienced lapidarist may be able to obtain satisfactory results by taking extra care in cutting and polishing this somewhat crystalline stone to avoid/minimize the orange peel effect ("pitting") .  The use of stabilizing agents is helpful in this regard.  We have obtained good results by using sodium silicate solution ("water glass").  We purchase this solution from http://www.postapplescientific.com/. We estimate the MOHs hardness to be approximately 5.0 to 6.5.

This specimen material makes a great addition to any rockhound collection.  Also, we just recently learned that it can be used to make purple pigment.  Vesuvianite is also highly prized by New Age adherents.

Lapis Lazuli

Lapis lazuli has a history reaching back to 5000 BC.  Deep blue in color and opaque, this gemstone was highly prized by the pharaohs of Egypt.  Similarly, in ancient times, lapis lazuli was known as sapphire (see Biblical reference in the Book of Job, Chapter 28, verses 6 and 16).  It is still extremely popular today.  The name derives from the Latin lapis, which means stone, and from the Persian lazhward, which means blue.

The finest lapis has traditionally come from the Badakshan area of Afghanistan.  This source of lapis may be the oldest continually worked set of mines in the world, the same mines operating today having supplied the lapis of the pharaohs.  In addition to the Afghan deposits, lapis has been found in Pakistan and (in lower qualities) in the Andes Mountains of Chile.  The lapis sold by Rock and Jewelry Sensations is genuine Afghan lapis.

The finest color is intense blue, lightly dusted with small flecks of golden pyrite.  There should be no white calcite veins and the pyrite inclusions should be small.  Stones that contain too much calcite or pyrite are not as valuable.  Patches of pyrite play an important role in identifying the stone as genuine and do not detract from its value.

Lapis takes an excellent polish and is made into jewelry, carvings, boxes, mosaics, ornaments and vases.  It has been used in architecture for cladding the walls and columns of palaces and churches.  It also has been ground and processed to make the pigment Ultramarine for tempera paint and, more rarely, oil paint.

Persian Turquoise

Turquoise is an opaque, blue-to-green hydrated copper aluminum phosphate mineral.  It is rare and valuable in finer grades and has been enjoyed as a gem and ornamental stone for thousands of years due to its unique coloring.

The word “turquoise” is very old and likely is derived from the French “pierre turquoise”, meaning “Turkish stone.”  This is thought to have come from a misconception since turquoise does not occur in Turkey but rather was traded there, and the gem became associated with that country in the West.  Interestingly, the color has been used extensively in the decorative tiles adorning Turkish places of worship and homes for hundreds of years so the association no doubt contributed to the name taking root.

Even the finest of turquoise is facturable, reaching a maximum hardness of just under 6 (the MOHS hardness scale).  The luster of turquoise is typically waxy to subvitreous, and the transparency is usually opaque, but may be semi-translucent in thin sections.  The color is as variable as the mineral’s other properties, ranging from white to a powder blue to a sky blue, and from a blue-green to a yellowish green.  Despite its low hardness relative to other gems, turquoise does take a good polish.

Turquoise was among the first gems to be mined, and while many historic sites have been depleted, some are still worked to this day.  In fact, the material sold by Rock and Jewelry Sensations was produced from a mine in Alaverdi, Armenia, across the border from the region in Iran that produced the ancient and highly prized Persian mines that are now mined out.