Citrine is the world’s best-selling gem with a yellow to orange color. It is a favorite gem because of its affordability and durability. It is durable because of its Mohs hardness of 7 and affordable because of its abundance. Citrine is not as easy to find in jewelry stores as blue topaz, but with a little…

Topaz is a birthstone for the month of November. It occurs in a wide range of natural and treated colors that include blue, pink, purple, yellow, brown, orange, and colorless. Topaz is a very durable stone with a Mohs hardness of 8. Diamond, ruby and sapphire are the only commonly used gemstones with a greater hardness.…

Tourmaline occurs in a wide variety of colors. The accompanying photo shows a collection of faceted tourmalines of various colors. Some of these stones exhibit multiple colors because they were cut from color-zoned crystals. Two are pink and green bicolor stones known as “watermelon tourmaline.” Bicolor and pleochroic tourmalines are favorite stones of many jewelry designers…

Opal is an original modern birthstone for the month of October. Some people call it the world’s most colorful gem because one stone can display a full spectrum of colors. Opal occurs many different varieties. The accompanying image is a black opal from Australia, but there are also fire opals from Mexico, honeycomb opals from Ethiopia, and colorful common opals from Peru. Lab-grown opals are available in a…

Sapphire is the birthstone for September. Most people immediately think of a blue gem when they hear the name “sapphire”. That is because gem-quality specimens of the mineral corundum with a blue color are called “sapphire” by definition. However, corundum occurs in many colors. When it is pink, orange, green, purple, yellow, or any of these other colors,…

Some (but not all) birthstone lists include sardonyx as a birthstone for August. Sardonyx is a banded variety of chalcedony that exhibits straight, parallel bands of white, black, orange, red, or brown chalcedony. Some of the most spectacular cabochons and beads are cut from sardonyx. Sardonyx has also been used as a material for cutting…

Spinel is a newcomer to birthstone jewelry. In July 2016, the American Gem Trade Association and the Jewelers of America named spinel a birthstone for the month of August. Being named a birthstone will do more for the popularity of spinel than millions of dollars spent on advertising. Spinel is the perfect birthstone. First, spinel occurs…

Peridot is a traditional birthstone for the month of August. It has a yellowish green color and is one of the world’s most popular and affordable green gems. Shoppers can expect to find it in almost every jewelry store. Peridot is the gem variety of a mineral group known as olivine. Much of the world’s peridot is…

Ruby is the birthstone for the month of July and the world’s most popular red gem. Rubies range in color from orangy-red, to red, to slightly purplish-red. The most desirable and valuable colors are pure red and slightly purplish red. Natural rubies have historically been expensive gems, but recent discoveries in Africa bring many attractive natural rubies into…

Moonstone is a feldspar mineral that produces a “pearly” luster when light enters the stone and is reflected by mineral layers within the gem. Moonstone is most often a white or gray color with a glow that is white or silvery – like the glow of the moon (that’s how it got its name!). Moonstone also occurs in…