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Limestone is composed mainly of calcite and occurs in thick extensive, multiple layers. It is formed in shallow seas from a combination of calcium carbonate or the accumulation of shells and skeletons of calcareous marine organisms. Limestone is abundant and is very important commercially as it has a number of different uses as a building stone, cement and as a raw material in the glass manufacturing process. Limestone that is recrystallized under heat and pressure becomes marble.

Smithsonite is named for James Smithson, the English founder of the Smithsonian Institution who first identified the mineral. Although it rarely forms crystals, smithsonite is most commonly found as botryoidal or stalactitic masses or as honeycombed aggregates. A member of the calcite group of minerals, smithsonite is prized for its variety of crystal forms. Smithsonite comes in a wide variety of colors depending on the impurities present. The presence of copper gives smithsonite its green to blue coloring. Trace amounts of cobalt are responsible for pink to purple hues while cadmium makes smithsonite yellow, and iron gives it a brown to reddish-brown color.

Coquina is a poorly cemented limestone that is composed of shells and remains of fossilized invertebrates like brachiopods, mollusks, and trilobites. It gets its name from the Spanish word for shellfish.

Labradorite is a plagioclase feldspar. The phenomenal variety that shows labradorescence is the best-known variety, but rainbow moonstone, Oregon sunstone, and transparent yellow labradorite are also labradorite feldspars. Displaying brilliant pastels and deep golden colors, phenomenal labradorite features a spellbinding "black rainbow" of color. When appreciating the iridescent play of colors known as labradorescence, observe the strength and intensity by viewing from different angles, as different colors or even a range of colors may be visible from different positions. Rainbow moonstone has the best transparency of all the moonstone varieties. Labradorite sunstone is the only sunstone variety that contains copper platelets. The large sizes and clarity of yellow labradorite makes it a favorite of gemcutters.

One of nature's more exotic treasures, rhodochrosite is a manganese carbonate that gets its name from two Greek words, rhodon meaning “rose” and chros, meaning “color.” This is a fitting name, indeed, as its finest colors range from very pale pink, to deep orangey red. Yellow to brown crystals are also known. Rhodochrosite comes in transparent, semi-translucent, and opaque varieties. Semi-translucent to opaque rhodochrosite is often carved or cut en cabochon and typically displays "bacon strip" or "bull's eye" patterns.

Alabaster is a fine-grained massive form of gypsum. Alabaster ranges from white to yellow, pink, and brown. Due to its porosity it is often dyed. It has been used for centuries for statues, carvings, and other ornamental purposes. Treated alabaster is used as a marble simulant. Due to its extreme softness, it is ideal for fashioning into works of art.

Nicknamed the "dragon stone," septaria has unique mineral patterns that resemble tree branches. Specimens are usually in the form of sliced nodules ranging from an inch in diameter to more than three feet across. They are estimated to have formed between 50 and 70 million years ago after periodic volcanic eruptions killed small sea life. The shells and carcasses of these creatures sank to the sea bed, where sediments accumulated around them to form nodules or balls of mud. When the waters eventually receded, the mud balls dried out and began to shrink and crack into the beautiful patterns that you see inside the septarian nodules.

Also called "rainbow calsilica," this is a man-made material that displays vibrant layers of bold color. It consists of a mixture of calcite, plastic and coloring pigments. This unique stone is often used in jewelry and carvings to show off its distinctive coloration.

Chrysocolla, derived from the Greek chrysos meaning "gold," is a copper mineral. Crystals are very rarely seen, but it is frequently intergrown with other minerals such as quartz or opal. This results in a harder, more resilient gemstone, as pure chrysocolla is soft and fragile. Its copper content is responsible for chrysocolla's range of bright green to blue hues.

Astrophyllite is golden-yellow to dark brown and usually forms as bladed crystals radiating from a common center. It gets its name from the Greek astron, meaning "star," and phyllon, meaning "leaf." It may also be translated as "star sheets" because of the interwoven star shapes that crystals sometimes form, and because of its strange luster, which can be metallic or pearly. Although there are occurrences of astrophyllite around the world, some of the finest crystals come from remote mountainous regions in arctic northern Russia.

Xaxim is a type of petrified tree fern from a period of time even before the dinosaurs roamed the earth. Estimated to be some 270 million years old, these fossilized specimens offer an exciting window into the past. Similar in appearance to the palm tree, xaxim trees can still be found growing in Brazil today. However, they grow very slowly, averaging about 3 inches every 10 years. Featuring all natural color with no enhancement, xaxim is prized by fossil collectors across the globe.

Blister pearls are large pearls that have intergrown with mollusks or freshwater mussels and are integrated with the shell. Solid “blister” pearls are akin to mabé pearls, but they are natural and not assembled. They are known to have a high luster and are more durable than mabé pearls. They are typically rounded or irregular in shape and have been known reach 2 cm in size. They are more often found in in larger Pinctadas molluscs. They are called “puku” in the Cook Islands. They are also found in freshwater river mussels in North America. The freshwater blisters pearls are often found in mussels with distorted shells and are come in irregular, round or button shapes. Snail blisters are created when small snails or mollusks invade the mussel shell. Blisters pearls have also been found in “Lion’s Paw Pearls” in Laguna Ojo de Liebre in Baja California, Mexico, and Conch pearls in the Caribbean.