Nealite: Informaion & Facts

Nealiteis a triclinic-pinacoidal mineral containing arsenic, chlorine, iron, lead, and oxygen. Nealite is a very rare mineral. It was named for an American mineral collector, Neal Yedlin. Nealite is known from one locality, its type locality of Lavrio (formerly Lavrion and Laurium), Greece.

Nealite and Phosgenite Locality: Lavrion Slag Localities, Lavreotiki, East Attica, Attiki Prefecture, Greece. Photo: Tomeik Minerals.

This locality has been mined for centuries starting with the Greeks and then the Romans for the lead content of its ores. The left over rocks, that were judged too poor in the metals to be processed by the ancient miners, were dumped into the sea. Such mining dumps are called slag dumps. Today these dumps are being reprocessed for their valuable metals by modern ore processing techniques that are capable of extracting the metals from these ores. Analysis of these rocks have yielded some amazing new minerals.

Some of these minerals were not there when the rocks were first mined centuries before. But they are there now! The sea water altered the low grade lead ores and produced a most unusual assortment of rare minerals of which nealite is one of them. Many people do not consider these minerals to be true minerals because their creation was indirectly aided by the actions of humans and therefore not exactly natural. Minerals must have a natural origin in order to be minerals. However, these minerals were only indirectly affected and the study of their origins is best left to mineralogists.

Nealite has a bright and attractive color. It is found only in microcrystals and is very hard to obtain for one's collection. But its beauty, rarity and interesting origin make it a very desirable mineral, especially for micromounters.

Nealite Crystals. Locality: Lavrion Slag Localities, Lavreotiki, East Attica, Attiki Prefecture, Greece Photo: Joy Desor Mineralanalytik

Properties of Nealite:

Chemical Formula:  Pb₄Fe²⁺(As³⁺O₃)₂Cl₄ · 2H₂O
Class: Phosphates
Subclass: Arsenates
Color is typically orange, also yellow.
Luster is vitreous.
Transparency: Crystals are transparent to translucent.
Crystal System is Triclinic.
Crystal Habits include platy prismatic to acicular crystals with a sharp domal termination.
Cleavage is absent.
Fracture is uneven.
Hardness is 4
Specific Gravity is approximately 5.88 (well above average for translucent minerals)
Streak is a pale orange yellow.
Other Characteristics: Crystals are brittle.
Associated Minerals include paralaurionite, georgiadesite and other rare lead slag minerals.
Notable Occurrences are limited to the type locality of Lavrio (formerly Lavrion and Laurium), Greece.
Best Field Indicators are color, crystal habit, high density, brittleness and locality.

It was discovered in specimen from the ancient Greek mines of Lauryon, in Attica (Greece), which is consequently its type locality.

Name: Named by Pete Dunn and Roland Rouse in 1980 for Leo Neal Yedlin (20 March 1908, Brooklyn, NY, USA - 7 October 1977, New Haven, CT, USA), American lawyer, author, and prominent mineral collector, who discovered the mineral. The mineral yedlinite is also named in his honor.

Nealite Crystals. From: Vrissaki Point slag locality, Vrissaki area, Attikí (Attica; Attika) Prefecture, Greece. Photo: Christian Rewitzer