Semi-Precious Gemstones M-R

In this glossary you will find a world of information on most of the materials we use in our handcrafted beaded jewelry designs at Bonnico Jewelry Designs. Featuring semiprecious gemstones from A to Z, different types of glass and lampwork beads, shells, differences in the types of the silver and gold we use and even birthstone colors and common jewelry sizes to help you decide if the size is right for you.

Malachite

Colors are dark and light green with black stripes. These stones can be found in the major deposits of Zaire, and also found in Australia, Chile, Namibia, the United States (Arizona) and Zimbabwe.

The beautiful green color comes from the copper contained in the stone which is an altered form of copper, and water presence affects the shade. The more water in the copper makes it lighter, and less water makes it darker. The absence of water makes it black. In fact, the green patina you see on weathered copper roofs is a form of malachite. Striations of green, light green, and black are malachite’s special feature. This stone scratches very easily and can become dull.

Mookaite

Colors are earthy flood of reds, yellows and browns. These stones can be found in Australia.

Mookaite is named for where it was first found in the outcrops, principally on Mooka Station (a sheep farm of around 700,000 acres), on the west side of the Kennedy Range in Western Australia. It is formed as sediment in erosion zones and as filler in cracks. In Australia, mookaite was and still is considered to be a healing stone that bestows strength. It is said to shield the wearer from difficult situations and to connect us to loved ones who have passed away.

Moonstone

Colors are white, yellow, and clear. These stones can be found in Brazil, India, Madagascar, Myanmar (Burma), Sri Lanka, and the United States.

Moonstone sometimes displays as a strong cat's eye. The floating-light phenomenon and sheen of moonstone are called adularescence or schiller. The light is scattered by alternating layers of two kinds of feldspar and produces a misty luster of white, dull yellow, yellow-gray or greenish-gray. The stone's main color also comes in shades of peach and gray. This stone is also a member of the feldspar family and are translucent beads. They have a shimmering quality and are often used as cabochons.

Obsidian

Colors are black, red-brown, dark gray. These volcanic stones can be found in Iceland, Italy, Japan, Java and the United States (Wyoming and Hawaii).

Obsidian is a natural glass that forms from volcanic activity. The gemstone is made of the same minerals as granite, but cools so quickly when exposed to air that the minerals do not have time to crystallize. Some inclusions could be bubbles or crystals, creating a random pattern such as snowflake.

Opal

Colors are white, pale yellow, brown, bluish-gray to dark gray, dark blue, dark green. These stones can be found primarily in Australia with additional deposits in Brazil, Guatemala, Honduras, Indonesia, Japan, Mexico, Russia, and the United States (Nevada and Idaho).

Opals are highly valued for the way their rainbow like hues creates a display of color in the stones. They diffract light at various wavelengths, creating multiple colors. All opals contain water, and the play of color diminishes when water is lost from the stones over time. The common opal, on the other hand, has a lesser play of colors.

Opals should be protected from heat and strong light, which can dry them out, causing cracks. In addition to cracking, loss of water causes loss of iridescence, therefore they might need to be oiled regularly to keep the water inside. Opals can be fairly brittle because they contain water so ultrasonic cleaners, metal polish, acids and any strong solvents also should be avoided.

Pietersite

Colors are mostly lavender-blue or light green colored mineral or more common colors are gray to gray-blue and some may have small inclusions of red or gold. The Chinese Pietersite has a unique gold color and just as beautiful as the African stones.

Pietersite was first discovered in Naibia, South Africa by Sid Pieters in 1962. To this day Pietersite is still mostly found in Namibia, South Africa but in 1993 it was also discovered around Nanyang, Henan, China. It was not exported to the West until 1997, when the Chinese became aware of its value.  

Did you know this stone is a variety of tiger-eye? This beautiful variety of tiger-eye is formed through a process when fibers of hawkeye, the blue variety of tiger-eye, and tiger-eye itself are broken down by the Earth's geological processes and then stimulated. The tiny sharp-angled fragments of the stones are essentially glued together by silica which is a impure form of quartz. It's color is a direct result of how the Earth forms the stone.

Pietersite has a connection to the storm element and may also be known as the Tempest Stone.  It is believed to hold the keys to the kingdom of heaven. Pietersite works well during meditation to reach higher levels of awareness and increasing intuition. Some of the healing  properties of Pietersite are used to stimulate the pituitary gland, balance endocrine system which aids growth, metabolism, blood pressure and body temperature.

Pearls

Colors will vary. Pearls can be found in Australia, Burma, China, Ceylon, Indonesia, Japan, Mexico, Norway, the Philippines, Scotland, Tahiti and the United States. The finest oriental pearls are found in the Persian Gulf.

The pearl is an organic gem grown within oysters and a few other mollusks. It is formed when a (foreign) tiny stone, makes its way into the mollusk's shell. The irritation caused by the foreign particle makes the oyster form a secretion, called nacre, to cover it. Nacre is the same material that forms the mollusk's shell. When dried, the particle again irritates the animal, so it begins to secrete again; as thousands of layers of nacre coat the intruder, a pearl is formed. The process takes anywhere from four months to seven years — the longer the process, the bigger the pearl.

A single mollusk can create dozens of pearls at a time, depending on how many particles enter the shell. "Cultured" pearls are those in which people, rather than nature, implant the intruding material, and the mollusks are cared for in a protective environment (a pearl farm) while coating process goes on.

Nearly all pearls available today are cultured, and only one out of four cultivated oysters’ lives to create a marketable pearl. Natural pearls are very rare and very valuable! So we assume the word "pearl" is a "cultured pearl" unless otherwise noted.

Peridot

Colors are yellow-green to olive green. These stones can be found in Australia, Brazil, China, Kenya, Mexico, Myanmar (Burma), Pakistan, South Africa, Sri Lanka, Tanzania, and the United States (Arizona).

Also know as olivine, the crusaders brought peridot to Central Europe in the Middle Ages. Later it was the Baroque era’s most popular stone. Peridot is created under immense temperatures and pressure deep within the Earth and sometimes is extruded in basaltic lavas. Its yellow-green color is mainly dependent on the amount of ferrous iron present. Peridot occasionally is treated with colorless oil, wax and natural or synthetic unhardened resins, which are placed into voids to improve appearance. Surface fractures are sometimes filled with a colorless hardened substance. It is safe to assume that any inexpensive peridot is treated in one of these ways.

Quartz

Colors will vary. Many varieties are found all throughout the world.

Quartz is a family of minerals with the same chemical composition (silicon dioxide) and similar physical properties. A Slavic word for “hard” quartz makes up a complete species of stone that comes in a variety of forms and colors. This includes amethyst, aventurine, and citrine. One of the most popular quartz varieties is the rose quartz, which is a pink stone.

Some more popular man made quartz gemstones consists of:

Blue Quartz - dense, stormy-blue swirls, opaque.

Blueberry Quartz - deep-blue needles are dispersed throughout the clear glass.

Cherry Quartz - pretty mixture of clear glass with thin swirls and needles of pink cherry color.

Pineapple Quartz - clear glass containing thin swirls and needles of pale yellow.

Rhodochrosite

Colors are white, pink, rose-red, and brown. These stones can be found in major deposits in Argentina. Also found in Chile, Mexico, Peru, South Africa, and the United States.

This uniquely marbled stone has beautiful striations of various shades of pink, ranging from very light to a deep raspberry. It is rare to find transparent crystals of this stone. A manganese ore, Rhodochrosite appears in a banded pattern with various white minerals (often calcite) that give it the signature look sometimes called “raspberryspar”.

Rhodonite

Colors are deep rosy pink to lavender with characteristic black veins called dendrites. These stones can be found in Brazil, Mexico, Peru and the United States (Colorado).

Composed of manganese silicate, Rhodonite makes a more durable gemstone than Rhodochrosite, which is streaked with white minerals and is reactive to acids. Beads will have a rather flat finish; it does not take a good polish. Most cleaning methods are safe for Rhodonite (ultrasonic, etc), but like with all gemstones, avoid rough handling and extreme heat.

Rhyolite

Colors are mossy greens, browns and grays. These stones can be found in the Western and Southwestern United States and occasionally on the East Coast.

Rhyolite is an igneous rock with high silica content, chemically identical to granite. It cooled from a molten state, too quickly for crystals to form. Because Rhyolitic magma and lava are so thick, they tend to build up pressure until a gas explosion in the volcano throws them all over the place in particles ranging from ash all the way up to big blocky chunks. The stone's mossy greens, browns and grays are reminiscent of a rainforest, and it presents interesting banding.

Riverstone

Color is creamy beige and pale gray. These stones are found in rivers and beaches.

The stones become naturally polished as water and other rocks move against them.

Ruby

Color is red. These stones can be found in primary deposits in Myanmar (Burma), Sri Lanka, Tanzania, and Thailand.

Rubies are available in a range of reds. The most desirable color is “pigeon’s blood” a pure red with a hint of blue. After the diamond, a ruby is the hardest stone. Its hardness, durability, luster and rarity are among the worlds finest, and its blazing red color is beyond compare. Ruby is the red variety of the corundum (aluminum oxide) mineral, a family that also includes sapphire. Inclusions don't affect the gemstone's quality (unless they decrease the transparency), but rather are the gemstone's fingerprints.