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What is Anhydrite (Angelite)?

Angelite in hands

Rare and difficult to cut, anhydrite is seldom faceted. However, this material can be carved into beautiful objects. “Angelite,” a blue-gray variety, has become a popular choice for lapidary arts.

This translucent, blue-gray anhydrite variety known by the trade name “angelite” or “angeline” has become a popular gem material. Discovered in Peru, it was introduced to worldwide gem markets in the late 1980s. This material has been used for beads, spheres, and carvings. Of course, these trade names carry deliberate angelic connotations. The gem’s color may evoke sky blue or, perhaps, a “heavenly” blue.

Does Anhydrite Make a Good Jewelry Stone?

Anhydrite doesn’t occur in abundance. When exposed to water over time, it alters into the much more commonly found gypsum. Not surprisingly, facetable material is rarer still.

With excellent cleavage planes in three directions, anhydrites also prove challenging to cut and fragile for wear. Furthermore, with a hardness range of 3-3.5, they’re very susceptible to scratching, which further limits their use as jewelry stones. Avoid ring use and use protective settings whenever possible with this gem. Consider creating earrings, pendants, and bracelets, instead. Artisans have carved objects and cut cabochons from this material. Of course, carvings and decorative objects will hopefully face fewer risks than jewelry.

Close-up view of a polished anhydrite stone showcasing brown and yellow bands with intricate patterns.
Anhydrite Bowel Stone (2)

Other Anhydrite Varieties

Although angelite is the most well-known anhydrite variety, various types of anhydrites with lapidary uses or unusual appearances have also received trade names. (1)

  • Bowel Stone
    Anhydrite that occurs in folded, concretionary forms is known as bowel stone. This variety name also carries deliberate connotations.
  • Blue “Egyptian” Anhydrite
    The Ancient Egyptians used white anhydrite as well as a distinctive blue-tinted variety to create beautiful objects. However, the ancient source of the blue material, which takes a good polish, has never been found.
  • Vulpinite
    This white-gray, marble-like textured material from Volpino, Italy is used locally for cabs and as a decorative stone.

Identifying Characteristics

Because of the intersection of anhydrite’s cleavage planes at right angles, these gems may break apart and reveal cube-like (pseudo-cubic) forms. This appearance has led to another name for this gemstone: “cube spar.” Despite appearances, anhydrites have an orthorhombic crystal habit, not a cubic or isometric habit. (1)

Blue “Egyptian” Anhydrite (2)

How to Care for Anhydrites

Keep any anhydrites dry, especially if placed in storage. They will readily absorb moisture and, over time, turn wholly or partly into gypsum.

Don’t wipe dust off anhydrites. Since household dust consists mostly of silicon quartz, which is far harder (7) than anhydrites, you’ll scratch them. Pat them with a lint-free cloth, instead. (1)

Sources
(1) International Gem Society
(2) FreePik

In My Shop

Angelite and Agate Necklaces

Angelite and Agate Necklaces

$32.00

These Angelite and Agate Necklaces are composed of 8mm Natural Green Angelite Gemstone, 8mm Natural Blue Dragon Agate, silver-plated round spacer beads and magnetic clasps.

2 in stock

SKU: SJDB149
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What is Polymer Clay?

Polymer Clay Selection

Polymer clay is a type of hardenable modeling clay based on the polymer polyvinyl chloride (PVC). It typically contains no clay minerals, but like mineral clay a liquid is added to dry particles until it achieves gel-like working properties. Similarly, the part is put into an oven to harden, hence its colloquial designation as clay. Polymer clay is generally used for making arts and craft items, and is also used in commercial applications to make decorative parts. Art made from polymer clay can now be found in major museums.

Bakelite, an early plastic, was popular with designers and was an early form of polymer clay, but the phenol base of uncured Bakelite was flammable and was eventually discontinued. Polymer clays were first formulated as a possible replacement for Bakelite. One of these formulations was brought to the attention of German doll maker Käthe Kruse in 1939. While it was not suitable for use in her factory, Kruse gave some to her daughter Sophie, who was known in the family as “Fifi”, who successfully used it as modeling clay. The formulation was later sold to Eberhard Faber and marketed under the name “FIMO” (FIfi’s MOdeling compound).

Polymer clay earrings
Polymer Clay Earrings (2)

Polymer clays contain a basis of PVC resin and a liquid plasticizer,[4] making it a plastisol. Polymer clay plastisol is also categorized as a plastigel because of its rheological properties.[5] It is a high yield thixotropic material: when a sufficient force is applied, the material yields, flowing like a viscous liquid until that force is removed, whereupon it returns to being a solid. This plasticity is what makes it useful as modeling clay as opposed to putty or paste. Plastigels retain their shape even when heat is applied, which is why polymer clay does not melt or droop when oven cured. Various gelling agents are added to give it this property, such as aminated bentonite, metallic soaps, or fumed silica.

The base resin can be modified in various ways. Mineral oil, lecithin, and odorless mineral spirits can be added to reduce its viscosity or alter its working properties. Small amounts of zinc oxide, kaolin, or other fillers are sometimes added to increase opacity, elastic modulus, or compression strength. Polymer clay is available in many colors, which can be mixed to create a wide range of colors or gradient blends. Special-effect colors and composites include translucent, fluorescent, phosphorescent, and faux “pearls”, “metallics”, and “stone.”

Polymer clay remains workable until cured. Curing occurs at temperatures from 265 °F (129 °C) to 275 °F (135 °C) sustained for 15 minutes per 1⁄4 inch (6.4 mm) of thickness.[1] This temperature is significantly less than for mineral clays and can be achieved using a home oven. Professional polymer clay brands shrink very little when cured. Brands of polymer clay include Cernit, Oytra, Fimo, Kato Polyclay, Sculpey, PVClay Brasil, Crafty Argentina and Cosclay.

home pasta-making machine
Home Pasta-making Machine (3)

A home pasta-making machine is a popular multi-purpose tool for polymer clay artists. It is used to create sheets of uniform thickness, to mix colors or create variegated sheets, and to condition (soften) the clay. Polymer clay generally needs to be conditioned before use. This involves kneading the clay by hand, passing it between two rollers, or using a low-shear mixer to break up any resin particle adhesions. Once conditioned, the clay will remain pliable until the particles eventually re-adhere.

Oven-hardenable PVC plastisol, “liquid polymer clay,” is a complement to polymer clay that can be used as an adhesive to combine pieces, or to create various effects. Pigments, chalk pastel, and regular polymer clay can be added to make colored liquid clay. The liquid can also be poured into molds to produce cast parts. (1)

In My Shop

White Pink Heart Earrings

White Pink Heart Earrings

$23.00

These White Pink Heart Earrings are composed of Polymer Clay and Gold-Plated Earring Components including Studs

SKU: SJDB154
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Sources

(1) Wikipedia
(2) FreePik
(3) Sculpey

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What is Aquamarine?

Aquamarine stone

What is Aquamarine? Named after the color of sea water, aquamarine is the blue to blue-green member of the beryl family. Readily available and moderately priced, the modern March birthstone makes an excellent jewelry stone.

White Blue Chocolate Candy Aquamarine [2]

What is the Color of Aquamarine?

This beautiful gem receives its coloring from trace amounts of ferrous iron. Its hues range can range from blueish green, blue-green, greenish blue, to deep blue, and its tones can vary from very light to moderately dark. You’ll rarely see aquamarines darker than a Swiss blue topaz. When you do, the color is usually enhanced by the cut.

You might encounter gemstones sold as “white aquamarines.” Be aware that such stones are most likely colorless beryls, also known as goshenites.

What Does Aquamarine Symbolize?

In Western cultures, due to aquamarine’s color and name, this gem has a folklore strongly connected to the sea. Its mystical purview traditionally includes protection for sailors and fishermen as well as travelers in general.

What Inclusions do Aquamarines Contain?

Inclusions are interesting features of this gemstone. Beryl, and aquamarine in particular, are known for having long, hollow tubes. This distinctive feature can help identify a gem as a member of the beryl family.

Aquamarines may have transparent and metallic inclusions, such as biotite, hematite, ilmenite, phlogopite, pyrite, and  rutile in skeletal crystals. They may also contain crystals of apatite, cassiterite, epidote, garnet, muscovite; quartz, and tourmaline. Some stones contain “snow-stars,” irregularly shaped liquid droplets in a star formation. The Martha Rocha aquamarine has notable “snow-star” inclusions.

[2]

Aquamarine Cat’s Eyes and Star Stones

With enough hollow tube inclusions and proper cutting, aquamarines can show chatoyancy and even asterism. Collectors prize beautiful cat’s eye aquamarines very highly, and their prices come very close to that of clean, faceted gems with the same coloring. Star aquamarines are even more rare than cat’s eyes and can command premium prices.

Are There Lab-Created Aquamarines?

Aquamarines can be synthesized, and an examination under a microscope may find some indications of synthetic origin. However, professional gem labs have advanced instruments that can distinguish natural from created aquamarines.

Are Aquamarine Gemstones Enhanced?

Most aquamarines come out of the ground with a greenish tint, but this will disappear after heating to 375° C, which leaves a pure blue color. Removing aquamarine’s green tinting through heat treatment is very common. In the past, this was done routinely. Nowadays, a more sophisticated public has started appreciating slightly green, untreated aquamarines. However, distinguishing this heating process proves impossible. Therefore, gem graders should describe any pure blue aquamarines as “probably heat treated.”

In the 1970s, Maxixe (pronounced mah-SHE-she), a very dark blue aquamarine, appeared on the market, but the color of this irradiated product wasn’t stable. Although these stones have mostly disappeared from the market, if you’re ever offered a very deep blue aquamarine, buyer beware.

You can distinguish the Maxixe from a natural aquamarine by its lack of pleochroism. Natural aquamarines have distinct blue and colorless dichroism. On the other hand, the Maxixe has no pleochroism. When viewed from any angle, it just shows blue. The absorption spectrum of natural aquamarine and the Maxixe also differs. With a spectroscope, you’ll see a narrow line at 6950, a strong line at 6540, and weak lines at 6280, 6150, 5500, and 5810. This differs considerably from natural aquamarine’s spectrum, with a broad band at 4270 and a diffuse band at 4560.

You can also distinguish a Maxixe aquamarine from a natural stone with a dichroscope. Both windows remain blue when viewing a Maxixe. In contrast, one window should be colorless or pale yellowish when viewing an untreated specimen.

Where are Aquamarine Gemstones Found?

  • Brazil is the world’s major source of fine aquamarine gems. Localities include Minas Gerais, Rio Grande do Norte, Ceara, and others.
  • Madagascar has more than 50 specific localities that produce fine, blue gem material.
  • Other notable sources include the following:
  • United States: San Diego County, California (not much gem material); Mt. Antero, Colorado; Connecticut (some gem); Maine; North Carolina.

Aquamarine Trade Names

  • Brazilian aquamarine: blueish green. Also a misnomer for blueish green topaz.
  • Madagascar aquamarine: fine, medium blue.
  • Maxixe beryl: treated beryl with excellent aquamarine blue, known for fading. Also called halbanite.
  • Santa Maria aquamarine: medium-dark tone and highly saturated blue color.
  • Don’t assume aquamarines billed as “Brazilian” or “Madagascar” actually come from these sources. These terms may only refer to the color, so ask to see documentation to certify a gem’s origin. “Santa Maria” aquamarines are named after the Santa Maria de Itabira mine where they were first discovered, but stones with similar colors have also been found in other locations.

In My Shop

Aquamarine Necklace and Earrings Set

Sources

[1] International Gem Society
[2] Photos by Freepik