Gemstone reference
A quick guide to common loose gemstones, their hardness, typical colors, and rough per-carat value ranges.
Countries listed are major or notable sources, not every deposit. Prized origins describe market reputation, not a guaranteed highest value: color, clarity, size, cut, treatment and verified origin matter.
A popular purple quartz, affordable and widely available.
Hardness
7
Typical value/carat
USD 20 – 150
Clarity note: Usually eye-clean; darker saturated stones are more valuable.
Countries where found
Brazil, Uruguay, Zambia, Namibia, Mexico, Russia, Bolivia, Sri Lanka
Prized origins / high-value examples
No single country: origin alone does not add value; color is the key value factor.
Brazil is a major source, while fine historic material is associated with Russia; do not equate geographic reputation with a guaranteed quality premium.
A pale blue to blue-green beryl, member of the beryl family.
Hardness
7.5
Typical value/carat
USD 200 – 1,500
Clarity note: Often eye-clean; deeper blue commands higher prices.
Countries where found
Brazil, Nigeria, Madagascar, Mozambique, Pakistan, Afghanistan, United States
Prized origins / high-value examples
Brazil — renowned for fine deeply colored aquamarine; no universal country ranking.
Santa Maria is a Brazilian locality associated with deep blue aquamarine; the color name alone does not prove Brazilian origin. Color, clarity, size and cut determine individual value.
A yellow-to-orange quartz often used as a budget-friendly gem.
Hardness
7
Typical value/carat
USD 20 – 200
Clarity note: Often clean; natural citrine is rarer than heat-treated amethyst.
Countries where found
Brazil, Zambia, Bolivia, Madagascar
Prized origins / high-value examples
No single country; prized color is saturated yellow to reddish orange without brownish tints.
Natural citrine is rare; much commercial citrine is heat-treated amethyst, commonly from Brazilian material, so disclose natural versus treated rather than implying origin determines value.
The hardest natural gemstone, valued for brilliance and durability.
Hardness
10
Typical value/carat
USD 2,000 – 50,000
Clarity note: Clarity graded from flawless to included; cut strongly affects value.
Countries where found
Botswana, Russia, Canada, South Africa, Angola, Democratic Republic of the Congo, Australia
Prized origins / high-value examples
No single country; diamond value depends on the individual stone and market factors, not a universal country hierarchy.
Country of extraction is distinct from diamond quality and can be difficult to establish for an individual stone; source listings reflect production at particular times and are not a current ranking.
A green beryl loved for its rich color, though softer and included.
Hardness
7.5
Typical value/carat
USD 400 – 10,000
Clarity note: Almost always included; acceptable inclusions are common.
Countries where found
Colombia, Zambia, Brazil, Afghanistan, Pakistan, Ethiopia
Prized origins / high-value examples
Colombia — renowned for exceptional fine emeralds.
Origin premiums, when present, are specific to market and material; color, clarity, treatment, size and the verified origin of an individual stone matter. Colombian and Zambian emeralds have different deposit characteristics.
A family of minerals with many colors; red garnets are classic.
Hardness
6.5
Typical value/carat
USD 50 – 3,000
Clarity note: Almandine/rhodolite often included; tsavorite/demantoid cleaner.
Countries where found
Tanzania, Kenya, Madagascar, Mozambique, Namibia, Nigeria, United States, India, Sri Lanka
Prized origins / high-value examples
Variety-dependent: Kenya and Tanzania (tsavorite); Namibia and Nigeria (bright orange spessartine).
Do not generalize across garnet species: tsavorite is associated with Kenya and Tanzania, while notable bright orange spessartine includes Namibia and Nigeria; value is also strongly variety- and quality-specific.
A feldspar known for its billowy adularescent sheen.
Hardness
6
Typical value/carat
USD 30 – 400
Clarity note: Adularescence is the key value factor; often translucent.
Countries where found
Sri Lanka, India, Madagascar, Myanmar, Tanzania
Prized origins / high-value examples
Sri Lanka — renowned for fine blue-sheen moonstone.
Moonstone names cover feldspar materials with differing appearance: Sri Lankan material is known for blue sheen, while Indian material often has a more body-color/white sheen; these are tendencies, not guarantees of quality or value.
A silica gem prized for its unique play-of-color patterns.
Hardness
6
Typical value/carat
USD 100 – 5,000
Clarity note: Body tone and play-of-color determine value; often translucent.
Countries where found
Australia, Ethiopia, Mexico, Brazil, United States
Prized origins / high-value examples
Australia — particularly fine black opal from Lightning Ridge.
Specify opal type: Australia is associated with black and white precious opal and boulder opal; Ethiopia produces hydrophane precious opal, whose water sensitivity is a material-specific caveat. Body tone, play-of-color, pattern, stability and treatment matter.
A vivid green gem formed deep in the earth, often with inclusions.
Hardness
7
Typical value/carat
USD 50 – 500
Clarity note: Often has a sleepy or slightly included appearance.
Countries where found
United States, China, Pakistan, Myanmar, Vietnam, Egypt, Tanzania, Ethiopia, Finland
Prized origins / high-value examples
Myanmar and Pakistan are often associated with especially fine-color material; not a universal ranking.
Sources vary by deposit type; commercial sources include basalt-hosted material and historic vein deposits. Quality is not determined by origin alone.
A precious red corundum prized for vivid color and hardness.
Hardness
9
Typical value/carat
USD 500 – 15,000
Clarity note: Often included; eye-clean stones command premium.
Countries where found
Myanmar, Mozambique, Madagascar, Thailand, Sri Lanka, Tanzania, Vietnam, Afghanistan
Prized origins / high-value examples
Mogok, Myanmar, is historically renowned; fine rubies also come from other origins, including Mozambique.
Mogok is a historic district, not a country. Origin premiums are market- and stone-specific; treatment, color, clarity, size, and documentation matter.
A precious corundum available in many colors, best known in blue.
Hardness
9
Typical value/carat
USD 300 – 8,000
Clarity note: Typically cleaner than ruby; Kashmir/Ceylon origins valued.
Countries where found
Sri Lanka, Myanmar, Madagascar, Australia, Thailand, Cambodia, United States, Tanzania, India (historical Kashmir deposits)
Prized origins / high-value examples
India — historical Kashmir blue sapphires; Myanmar and Sri Lanka are also prized.
Kashmir is a region, not a country. The famous historical sapphire mines lie in Indian-administered Kashmir. Exceptional velvety-blue examples can command origin premiums; not every Kashmir sapphire is more valuable than stones from elsewhere.
A durable gemstone prized for its vivid colors; red spinel has historically been mistaken for ruby. The per-carat range is illustrative, not a current price quote; exceptional stones can exceed it.
Hardness
8
Typical value/carat
USD 500 – 15,000
Clarity note: Eye-clean stones are generally more valuable. Color, size, cut, origin and natural versus synthetic status strongly affect value; a photo cannot establish all of these.
Countries where found
Myanmar, Sri Lanka, Tajikistan, Vietnam, Tanzania, Madagascar
Prized origins / high-value examples
Myanmar — historical Mogok red spinel; Tanzania and Vietnam also yield prized colors.
The most prized origin depends on color and the individual stone. Fine red and cobalt-blue material belong to different market categories; no country guarantees the highest value.
A blue-violet zoisite found only in Tanzania.
Hardness
6.5
Typical value/carat
USD 150 – 1,200
Clarity note: Often eye-clean; pleochroic, showing blue/violet/brown.
Countries where found
Tanzania
Prized origins / high-value examples
Tanzania (the sole commercial source, Merelani Hills).
Tanzanite is the blue-violet variety of zoisite; it is mined commercially only at Merelani in Tanzania. Heat treatment is common and affects color.
A hard, versatile gem best known in blue and imperial orange hues.
Hardness
8
Typical value/carat
USD 100 – 2,500
Clarity note: Usually clean; imperial topaz is most valuable.
Countries where found
Brazil, Pakistan, Russia, Nigeria, Sri Lanka, United States, Mexico
Prized origins / high-value examples
Brazil — especially rare imperial topaz.
Imperial topaz is a variety/color designation, not a synonym for all topaz. Color, treatment, rarity, and quality should be considered separately from origin.
A colorful gemstone family that can display two or more colors.
Hardness
7
Typical value/carat
USD 100 – 2,500
Clarity note: Can show color zoning; clean, vivid stones are prized.
Countries where found
Brazil, Mozambique, Nigeria, Afghanistan, Pakistan, Madagascar, United States, Namibia
Prized origins / high-value examples
Brazil — especially rare copper-bearing Paraíba tourmaline.
Paraíba-type refers to vivid copper-bearing blue-to-green tourmaline, not solely Brazilian material. GIA reports that origin assessment requires quantitative analysis and that all three countries produce it.
An opaque blue-to-green phosphate prized since antiquity.
Hardness
5
Typical value/carat
USD 50 – 1,500
Clarity note: Often porous and treated; matrix patterns affect value.
Countries where found
Iran, United States, China, Egypt, Mexico, Chile
Prized origins / high-value examples
Iran — traditionally prized fine blue turquoise from Nishapur.
Turquoise is an opaque mineral with quality strongly influenced by color, texture, matrix, and treatment/stabilization; traditional reputation is not a universal value ranking.