Gemstone Guide

A guide to the gemstones we sell beads in: what each stone is, how to tell it apart, how to look after it, and the folklore that has grown up around it. Choose a stone to read more.

Agate – Agate is a banded variety of chalcedony, the microcrystalline form of quartz (silicon dioxide).
Amethyst – Amethyst is the purple variety of quartz and the most valued member of the quartz family.
Ametrine – Ametrine is a naturally occurring variety of quartz that combines amethyst (purple) and citrine (yellow to orange) in the same crystal, in distinct colour zones.
Aquamarine – Aquamarine is the pale blue to blue-green variety of the mineral beryl, the same mineral as emerald.
Botswana Agate – Botswana agate is a finely banded agate (a variety of chalcedony, microcrystalline quartz) found mainly in the Bobonong district of eastern Botswana, near the borders with South Africa and Zimbabwe.
Bronzite – Bronzite is an iron-rich variety of enstatite, a mineral of the pyroxene group.
Carnelian – Carnelian is a translucent orange to reddish-brown variety of chalcedony, the microcrystalline form of quartz.
Chrysocolla – Chrysocolla is a hydrated copper silicate mineral with beautiful blue, blue-green and turquoise-like colours.
Chrysoprase – Chrysoprase is a translucent apple-green to bluish-green variety of chalcedony, the microcrystalline form of quartz.
Citrine – Citrine is the yellow to golden-orange variety of quartz.
Common Opal – Common opal, also called "potch" by opal miners, is opal that does not show play-of-colour.
Coral – Coral is an organic gem, formed from the hard skeletons of colonies of tiny marine animals called polyps.
Emerald – Emerald is the green variety of the mineral beryl and one of the four traditional "precious" gemstones, alongside diamond, ruby and sapphire.
Fire Opal – Fire opal is a transparent to translucent opal with a warm body colour ranging from yellow through orange to bright red.
Fluorite – Fluorite (calcium fluoride) is often called "the most colourful mineral in the world".
Freshwater Pearl – Freshwater pearls are organic gems formed inside freshwater mussels living in rivers, lakes and ponds.
Garnet – Garnet is not a single mineral but a group of closely related silicate minerals that share the same crystal structure but differ in their chemical make-up.
Goldstone – Goldstone is a man-made glass, not a natural gemstone.
Green Aventurine – Green aventurine is a variety of quartz that contains small, flat, reflective inclusions of fuchsite, a green chromium-bearing mica.
Hematite – Hematite is an iron oxide mineral and one of the most important ores of iron.
Howlite – Howlite is a calcium borosilicate mineral, usually found as white or creamy nodules with fine grey or black web-like veining.
Jadeite – Jadeite is one of the two quite different minerals that are sold as jade, the other being nephrite.
Jasper – Jasper is an opaque, impure form of microcrystalline quartz (chalcedony), containing up to 20 percent or more of other minerals.
Labradorite – Labradorite is a calcium-rich plagioclase feldspar, famous for its striking play of colour, known as labradorescence.
Lapis Lazuli – Lapis lazuli is a deep blue metamorphic rock rather than a single mineral.
Lepidolite – Lepidolite is a lithium-bearing mineral of the mica group.
Magnesite – Magnesite is a magnesium carbonate mineral.
Malachite – Malachite is a copper carbonate mineral known for its vivid green colour and distinctive light and dark green bands and swirls.
Moonstone – Moonstone is a variety of feldspar, made up of very thin, alternating layers of two feldspar minerals, orthoclase and albite.
Nephrite – Nephrite is one of the two minerals sold as jade, the other being jadeite.
Obsidian – Obsidian is a natural volcanic glass formed when lava rich in silica cools so quickly that crystals do not have time to grow.
Onyx – Onyx is a variety of chalcedony (microcrystalline quartz) with straight, parallel bands of contrasting colour, unlike the curved bands of most agate.
Peridot – Peridot is the gem variety of the mineral olivine (forsterite), one of the few gemstones that comes in only one colour: green.
Precious Opal – Precious opal is opal that shows play-of-colour: flashes of spectral colours that shift and change as the stone is moved.
Prehnite – Prehnite is a calcium aluminium silicate mineral, best known in its soft, translucent green to yellowish-green colour, often with a gentle, glowing appearance.
Quartz – Quartz (silicon dioxide) is one of the most common minerals on Earth, making up about 12 percent of the Earth's crust.
Red Aventurine – Red aventurine is a variety of quartz coloured by fine inclusions of hematite or goethite, iron oxide minerals that also give the stone its sparkle (aventurescence).
Rose Quartz – Rose quartz is the pale to medium pink variety of quartz.
Ruby – Ruby is the red variety of the mineral corundum (aluminium oxide).
Sapphire – Sapphire is the gem variety of the mineral corundum (aluminium oxide) in every colour except red, which is ruby.
Sardonyx – Sardonyx is a variety of onyx, the parallel-banded form of chalcedony (microcrystalline quartz).
Sodalite – Sodalite is a deep royal blue mineral, usually streaked or veined with white calcite and sometimes with grey or black patches.
Synthetic Opal – Synthetic opal, also called created or lab-grown opal, is opal made in a laboratory with the same basic structure as natural precious opal: tiny spheres of silica arranged in an orderly grid that produce play-of-colour.
Tanzanite – Tanzanite is the blue to violet variety of the mineral zoisite.
Tiger's Eye – Tiger's eye is a variety of quartz known for its golden to reddish-brown colour and silky, shifting bands of light.
Topaz – Topaz is an aluminium silicate mineral containing fluorine.
Tourmaline – Tourmaline is not a single mineral but a group of closely related boron silicate minerals, and it occurs in a wider range of colours than almost any other gemstone.
Turquoise – Turquoise is an opaque, blue to green mineral, a hydrated phosphate of copper and aluminium.
Zoisite – Zoisite is a calcium aluminium silicate mineral that occurs in a range of colours, from green, grey and brown to pink, blue and violet.