Semi-Precious Stones A to Z: A Guide to Gemstone Beads

Semi-precious is a trade term for every gemstone other than the 4 traditional precious stones: diamond, ruby, sapphire and emerald. It describes custom, not quality or value; a fine aquamarine or tanzanite can cost more than a heavily included ruby, and the word says nothing about how hard or durable a stone is. The FTC's Jewelry Guides still use the phrase "precious or semi-precious stone" (16 CFR 23.25). Below is an A to Z of the semi-precious stones in our gemstone beads collection, each with its color, hardness and a link to shop it.

What Does Semi-Precious Mean?

The split between precious and semi-precious goes back centuries and reflects which stones the Western jewelry trade prized most when the lists took shape. It is not a scientific category: mineralogists group stones by chemistry and crystal structure, and many gemologists simply say "gemstone." Amethyst shows how loose the line is. It was ranked with the precious stones until large deposits in Brazil made it common.

The term still has a place in US guidance. The FTC's Jewelry Guides refer to "any other precious or semi-precious stone" when they set out how gem names may be used (16 CFR 23.25), and a related section (16 CFR 23.27) says it is deceptive to call a man-made product precious or semi-precious. For more on the vocabulary, see the difference between crystals and gemstones.

The 15 Stones We Carry in the Most Styles

These are the stone types with the most listings in our shop. Hardness is on the Mohs scale, where 7 (quartz) is a good benchmark for everyday wear; our Mohs hardness guide explains why.

Stone	Color	Hardness
Quartz	Clear, pink, smoky, purple, yellow	7
Jasper	Patterned reds, yellows, greens, browns	6.5 to 7
Agate	Banded, in nearly every color	6.5 to 7
Chalcedony	Translucent gray, blue, white and more	6.5 to 7
Jade	Green, white, black, lavender	6 to 7
Amethyst	Lilac to deep purple	7
Tourmaline	Black, pink, green, watermelon	7 to 7.5
Moonstone	White, peach, gray, rainbow, with a glow	6 to 6.5
Labradorite	Gray with blue and gold flash	6 to 6.5
Lapis lazuli	Deep blue with gold flecks	5 to 5.5
Opal	Pink, yellow, blue, white	5.5 to 6.5
Apatite	Teal to ocean blue	5
Tiger's eye	Golden brown with a silky sheen	6.5 to 7
Kyanite	Streaky blue to teal	4.5 to 7
Amazonite	Blue-green with white streaks	6 to 6.5

The Precious Exceptions

Diamond, ruby, sapphire and emerald are the 4 precious stones, and older lists sometimes added pearl. Three of them are in our shop: ruby, red corundum at 9; sapphire, blue and fancy colored corundum, also 9; and emerald, green beryl at 7.5 to 8. Our corundum beads collection brings ruby and sapphire together.

Semi-Precious Stones A to Z

Each entry gives what the stone is, its usual colors and its Mohs hardness.

A

African turquoise: a speckled blue-green jasper sold under a trade name, not true turquoise; about 6 to 7.

Agate: banded chalcedony quartz in nearly every color; 6.5 to 7.

Amazonite: a blue-green microcline feldspar streaked with white; 6 to 6.5.

Amethyst: purple quartz from pale lilac to deep grape; 7.

Angelite: a powder blue anhydrite from Peru; 3.5.

Apatite: a vivid teal to ocean blue calcium phosphate; 5.

Aquamarine: the pale to sea blue variety of beryl; 7.5 to 8.

Aventurine: quartz that sparkles with tiny mineral flakes, most often green; 6.5 to 7.

Azurite: a deep azure copper carbonate, often mixed with green malachite; 3.5 to 4.

B

Beryl: the mineral family of aquamarine, emerald, pink morganite and yellow heliodor; 7.5 to 8.

Bloodstone: dark green chalcedony with spots of red iron oxide; 6.5 to 7.

Botswana agate: finely banded agate in gray, peach and pink; 6.5 to 7.

Bronzite: a brown pyroxene with a bronze metallic shimmer; 5.5 to 6.

C

Calcite: a soft calcium carbonate in blue, orange, honey and white; 3.

Carnelian: translucent orange to red chalcedony; 6.5 to 7.

Chalcedony: fine-grained quartz with a waxy glow, the parent of agate, onyx and carnelian; 6.5 to 7.

Charoite: a swirled lilac to purple stone found only in Siberia; 5 to 6.

Chevron amethyst: amethyst layered with white quartz in V-shaped bands; 7.

Chrome diopside: a deep forest green pyroxene colored by chromium; 5.5 to 6.

Chrysocolla: a blue-green copper silicate, often with brown matrix; 2 to 4.

Chrysoprase: apple green chalcedony colored by nickel; 6.5 to 7.

Citrine: yellow to amber quartz; 7.

Clear quartz: colorless rock crystal; 7.

Crazy lace agate: tightly swirled agate in cream, gray, red and gold from Mexico; 6.5 to 7.

D

Dendritic stones: opal and jasper marked with fern-like black dendrites of manganese oxide; 5.5 to 7.

Dragon's blood jasper: green epidote splashed with red piemontite; 6 to 7.

Dumortierite: a denim to violet blue borosilicate, often grown through quartz; about 7.

E

Eagle's eye: silvery gray quartz with a silky, shifting cat's-eye sheen like tiger's eye; 6.5 to 7.

F

Feldspar: the mineral family behind moonstone, labradorite, sunstone and amazonite; 6 to 6.5.

Fluorite: calcium fluoride in purple, green and banded rainbow colors; 4.

G

Garnet: a family of silicates best known in deep red, also orange and green; 6.5 to 7.5.

Golden sheen obsidian: black volcanic glass with a golden sheen; 5 to 5.5.

H

Hematite: a heavy, metallic gunmetal iron oxide, widely imitated by man-made hematine; 5.5 to 6.5.

Hematoid quartz: quartz coated or filled with yellow to red iron oxides; 7.

Howlite: a white borate with gray veins, often dyed to imitate turquoise; 3 to 3.5.

Hypersthene: a dark gray to black pyroxene with a silvery sheen; 5 to 6.

I

Iolite: violet blue cordierite that looks gray from other angles; 7 to 7.5.

J

Jade: the name for 2 minerals, nephrite (6 to 6.5) and jadeite (6.5 to 7), in green, white, black and lavender; see also green jade.

Jasper: opaque, patterned chalcedony-rich stone in reds, yellows, greens and browns; 6.5 to 7.

K

Kambaba jasper: a dark green stone patterned with black and green orbs, often sold as a fossil but in fact an orbicular volcanic rock from Madagascar (is kambaba jasper a fossil?); about 6.5 to 7.

Kunzite: a pink to lilac spodumene that can fade in strong sunlight; 6.5 to 7.

Kyanite: a streaky blue bladed aluminum silicate; 4.5 along the blade and 6.5 to 7 across it.

L

Labradorite: a gray feldspar that flashes blue, green and gold; 6 to 6.5.

Lapis lazuli: a deep blue rock of lazurite with white calcite and gold pyrite; 5 to 5.5.

Larimar: a sky blue pectolite found only in the Dominican Republic; 4.5 to 5.

Larvikite: a gray to black Norwegian feldspar rock with silvery blue flashes; 6 to 6.5.

Lava: light, porous black or gray basalt; about 6.

Leopard skin jasper: a cream, tan and pink orbicular rhyolite spotted with black; about 6.5.

Lepidolite: a lilac lithium mica, often set in harder quartz; 2.5 to 3 on its own.

M

Malachite: a banded green copper carbonate; 3.5 to 4 (real vs fake malachite).

Mica: a soft, shimmering sheet silicate in green, purple and brown; 2 to 3.

Mookaite: a red, mustard and cream chert from Western Australia; 6.5 to 7.

Moonstone: feldspar with a floating blue or white glow, in white, peach, gray and rainbow; 6 to 6.5.

Moss agate: clear to white chalcedony with green, moss-like mineral inclusions; 6.5 to 7.

O

Obsidian: volcanic glass, usually black, sometimes with a sheen or white snowflakes; 5 to 5.5.

Ocean jasper: orbicular jasper from Madagascar with circles of green, white, pink and cream; 6.5 to 7.

Onyx: solid black or banded chalcedony; 6.5 to 7.

Opal: hydrated silica in pink, yellow, blue and white, with or without play of color; 5.5 to 6.5.

P

Peridot: olive to lime green olivine; 6.5 to 7.

Petrified wood: ancient wood replaced by quartz that keeps its grain; 6.5 to 7.

Phosphosiderite: a lilac to purple iron phosphate; 3.5 to 4.

Pietersite: swirled, broken tiger's eye in gold, blue and red-brown; 6.5 to 7.

Pink opal: soft pink common opal; 5.5 to 6.5.

Prehnite: a pale green to yellow-green silicate, often with dark epidote needles; 6 to 6.5.

Pyrite: brassy iron sulfide known as fool's gold; 6 to 6.5.

Q

Quartz: the most common gem mineral, in clear, pink, smoky, purple and yellow; 7.

R

Red creek jasper: jasper patterned in red, orange, green and cream; 6.5 to 7.

Red jasper: brick red jasper colored by iron, including brecciated red jasper; 6.5 to 7.

Rhodochrosite: a rose pink and white banded manganese carbonate; 3.5 to 4.

Rhodonite: a pink manganese silicate with black veins; 5.5 to 6.5.

Rhyolite: a fine-grained volcanic rock in patterned earth tones, including Texas llanite; about 6 to 6.5.

Rose quartz: pale to medium pink quartz; 7.

Ruby zoisite: green zoisite studded with pink-red ruby and black hornblende; 6 to 6.5.

Rutilated quartz: clear quartz threaded with golden rutile or black tourmaline needles; 7.

S

Sardonyx: chalcedony banded in red-brown, black and white; 6.5 to 7.

Selenite: a silky white gypsum that water can damage; 2 (selenite vs satin spar).

Serpentine: a green to yellow magnesium silicate and the stone behind the trade name yellow jade; 3 to 5.

Sodalite: royal blue with white veins; 5.5 to 6.

Sodalite syenite: a gray rock whose sodalite glows orange under UV light; about 5.5 to 6.

Spinel: a hard magnesium aluminum oxide, mostly black in beads; 8.

Strawberry quartz: quartz with red to pink iron mineral inclusions; 7.

Sunstone: an orange feldspar that glitters from tiny metallic platelets; 6 to 6.5.

T

Tanzanite: violet blue zoisite found only in Tanzania; 6 to 7.

Tektite: black glass formed by meteorite impacts; 5 to 6.

Tiger's eye: golden brown quartz with a silky band of light that moves as it turns; 6.5 to 7.

Topaz: a hard, glassy silicate, mostly clear in beads; 8.

Tourmaline: a boron silicate in nearly every color, most often black; 7 to 7.5.

Turquoise: an opaque sky blue to green copper aluminum phosphate; 5 to 6.

U

Unakite: a granite of pink feldspar, green epidote and quartz; 6 to 7.

W

Watermelon tourmaline: tourmaline with a pink core and green rind; 7 to 7.5.

Y

Yellow opal: butter to lemon yellow common opal; 5.5 to 6.5.

Z

Zebra jasper: black and white striped stone; about 6.5 to 7.

Organic Gems

A few gems come from living things rather than rock. Amber is fossilized tree resin (2 to 2.5); coral is the calcium carbonate skeleton of marine animals (3 to 4); pearls are grown by mollusks, and nearly all on the market today are cultured (2.5 to 4.5); and mother of pearl is the iridescent nacre lining of a shell (about 3.5). Jet, a lignite formed from ancient wood, has its own story in the history of jet.

Frequently Asked Questions

What are semi-precious stones?

Every gemstone other than diamond, ruby, sapphire and emerald. The term reflects tradition, not a stone's quality, rarity or price.

What are the 4 precious stones?

Diamond, ruby, sapphire and emerald. Ruby and sapphire are both corundum, and emerald is a beryl, like aquamarine.

Is amethyst precious or semi-precious?

Semi-precious today. It was counted among the precious stones until large deposits in Brazil made it plentiful; read more in everything you need to know about amethyst.

Are semi-precious stones real?

They should be. Under the FTC Jewelry Guides (16 CFR 23.27), calling a man-made product precious or semi-precious is deceptive.

What is the hardest semi-precious stone?

Of the stones above, spinel and topaz at 8, followed by aquamarine and the other beryls at 7.5 to 8. Any stone of 7 or more is a good choice for rings and bracelets.

Shop Gemstone Beads

Browse all of our gemstone beads, or start with the big families: quartz, jasper and agate. To find the stone for each month, read the history and origin of birthstones.