Pectolite

Powellite is an unusual, molybdenum-containing mineral that appears in a variety of colors, though it is most commonly whitish or yellowish. The mineral was discovered in Idaho in the 1890s and was named for John Wesley Powell, a famed geologist and explorer who spent much time delving into the mineralogy and geology of the American west. Powellite is not used industrially or commercially, though some exceptionally-colored specimens may be sought after by collectors.

Titanite, also known as Sphene (especially when cut for gemstones), is a rare mineral occasionally mined as a source of titanium dioxide, used to create white pigments. Exceptional, gem-quality crystals, which are usually somewhere on the green-yellow spectrum, are highly sought after by collectors. Cut titanite has extremely high dispersion, or "fire" (i.e., white light passing through it is dispersed into many colors - diamonds are also famous for having high dispersion).

Tennantite is a usually dull, grey- or black-colored mineral that is a minor ore of copper, and evidence suggests that it has been smelted by humans to produce that useful metal since ancient times. First identified by geologists in Cornwall, England, tennantite is named after Smithson Tennant, an English chemist born in the 18th century.

Inesite is an appealing pinkish-brown translucent mineral that is sometimes confused with rhodonite. Its name comes from the Greek word for 'fiber' and refers to the sometimes fibrous appearance of this mineral. Inesite is uncommon to find in hydrothermal conditions often with manganese-rich metamorphic rocks. Its fracture is brittle and its streak is white.

Hornblendite is a rare igneous rock containing large amounts of hornblende, which is a combined group of dark-colored amphibole minerals. Hornblendite is often found alongside diorite, granite, gabbro, and peridotite. While uncommon, this rock is used for kitchen countertops, garden walkways and decoration, as well as entryway and flooring purposes.

Vauxite is a beautiful crystal occurring in light and dark transparent shades of blue. Vauxite crystals take on a flattened and parallel appearance, though the crystals vary in size. This secondary mineral can be found in apatite deposits in hydrothermal tin zones. Ferrivauxite is the oxidized result of vauxite.

Thaumasite is a rare mineral that occurs in the form of translucent or transparent hexagonal crystals. Although very attractive, thaumasite is quite soft and fragile, so you will usually find it cut into cabochons. Its name comes from the Greek word "thaumazein," meaning "to be surprised" or "to wonder," which refers to its unusual chemical compositions.

Clinochlore occurs in an attractive range of transparent and translucent dark greens. The fracture is uneven and the streak is white. No fluorescence is observed. Like other members of the Chlorite group, this mineral is pretty soft and has been used for carving and as decoration for hundreds of years.