First off please allow me to appologize for the delay. I have been working on other projects a lot lately and haven't found the time to keep this blog up-dated. Also please forgive the brevity of this post. Again this is due to my lack of time.
The zeolite mineral heulandite was named for John Henry Heuland, an English mineral dealer. It is one of the most common zeolites--a family of silicate minerals. Heulandite is often coral-pink, but it can also be brown, white or red. It has either a pearly or vitreous luster and a Mohs hardness of 3.5 to 4.
Heulandite’s crystals are an oddity among minerals. If they are not altered by a natural processes then they will be shaped like the coffins from Western movies. These crystals can be distorted during their formation, which causes them to look differently.
Heulandite can be used for the myriad of purposes that many other zeolites serve. It has no use in the jewelry industry, but collectors like me love to collect it!
Heulandite is found in basalt like many of its fellow zeolites. Sources of the mineral include: India, Iceland, the Faroe Islands, Scotland, the Canadian province of Nova Scotia, and the American states of Washington, Idaho, Oregon, and New Jersey.
Lepidolite is part of a group of minerals known as the micas, which I have written about before. I have chosen to cover lepidolite separately because it has a few unique properties, the most noticeable being its attractive color.
Ultimately, what sets lepidolite apart from the other micas is the presence of lithium in its chemical structure. In fact, one of the more common types of mica, muscovite, can be turned into lepidolite under the right conditions if lithium is present.
Lepidolite shares many traits with the other micas, but its individual chemical structure imparts a few properties that the others cannot claim. Like its cousins, lepidolite’s crystals are six-sided, very flat, and so soft that they are usually distorted. The crystals are often grouped as stacks and they’re commonly found as flakes. The thin crystals or flakes are flexible, a characteristic which is rare in the mineral kingdom. Lepidolite has a vitreous to pearly luster and a Mohs hardness of only 2.5 as do the other mica minerals.
Lepidolite’s first visible property that differs from lithium-free mica is its violet color, though it can take pale pink, or rarely gray or yellow. And it can be triboluminescent (when pressed it will emit little flashes of light in the dark.)
Lepidolite was once used as an ore of lithium, but the lithium content varies in lepidolite so people found other sources of the metal. Lepidolite is found chiefly within rock formations called “granite pegmatites” in places like: Madagascar, Sweden, the Brazilian state of Minas Gerias, and the American states of California, Connecticut, and Maine.
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