Natural Glass Gemstones: Properties, Meanings, Value & More
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natural glass gemstoneNatural glass gemstones can form on Earth or in space. These types of gems form when materials like rocks or sand become extremely hot and then rapidly cool, so quickly that they don’t crystallize.

There’s no understating the importance of glass — you wouldn’t be reading this article without it! But you probably hear “glass” and think “man-made,” right? Think again.

Nature — both on Earth and in outer space — has been forming glass for millennia, and lots of it is both beautiful and educational.

This guide covers the types of natural glass gemstones, their prices, history, benefits, and more!

natural glass gemstone

What is a Natural Glass Stone?

Many forms of natural glass are semi-precious gemstones. But what exactly is glass?

The scientific definition of glass is complex, but it’s considered a state of matter that may be liquid or solid (it’s hotly debated).

In mineralogy, glass is an amorphous (non-crystalline) material with a uniform make-up and random, liquid-like structure.

Natural glass like Libyan desert glass can substitute citrine as a November birthstone, and moldavite is lucky for Sagittarius.

Natural Glass Specifications & Characteristics

Most natural glasses are predominantly silicon. Glass stones are mineraloids, not minerals.

Is natural glass transparent? Not always. Many are translucent to transparent, but others can be opaque or have translucent to opaque edges.

How do you identify glass gemstones? Glass gemstones (natural and man-made) have characteristic round bubbles and swirls, along with concave facets and mold marks if they’re faceted.

But how do you identify natural glass? Many natural glasses have mineral inclusions that synthetic glass lacks.

Plus, many glass gems manufactured as gemstone imitations contain additives that can make their refractive indices and densities higher than natural glass.

So, what makes synthetic glass different from natural glass? Despite near-identical optical and physical properties, natural glass comes from nature and synthetic glass is processed.

Natural glass properties listed:

  • Mohs hardness: 5-6

  • Color: Often yellow, blue, or blue-green; Can be virtually any color depending on impurities

  • Crystal structure: None (amorphous)

  • Luster: Vitreous

  • Transparency: Transparent to opaque

  • Refractive index: 1.46-1.69 (varies by type)

  • Density: 2.2-3.0 (varies by type)

  • Cleavage: None

  • Fracture: Conchoidal

  • Streak: White

  • Luminescence: None

  • Pleochroism: None

  • Birefringence: None

  • Dispersion: None

  • Optical effects: Chatoyancy and iridescence possible for obsidian

Types of Natural Glass Gemstones

We’ll highlight examples of natural glass most often used as gems below.


natural glass obsidian gemstone carvingPictured above: Iridescent "rainbow" obsidian

Obsidian, often called simply “volcanic glass,” is the most popular natural glass gem. It forms from rhyolitic magma. Obsidian is usually shiny and black, often from magnetite inclusions.

Other impurities or inclusions can create different looks:

  • Iron Oxides: Reds and browns

  • Feldspars or Magnetite Nanoparticles: Iridescent, rainbow-like sheen

  • Trapped Gas Bubbles: Golden sheen

  • Radially Clustered Cristobalite Crystals: Snowflake pattern

  • Oriented Hedenbergite Nanorods: Colorful rainbow striping

Pumice is similar to obsidian but contains abundant holes from gas bubbles trapped in the ejected lava.


natural glass tektite moldavite gemstone facetedPictured above: Moldavite gemstone

Tektites are a type of impact glass formed when a meteorite impact causes material to rapidly melt, fly into the air, then rapidly cool into glass as it falls back to Earth.

Types of tektite glass are generally named for the “strewn fields” where they’re found, such as:

  • Moldavite: From Moldau River in Czechia

  • Libyan Desert Glass: From Libyan Desert

  • Australite: From Australia

  • Ivorites: From Ivory Coast

  • Darwin Glass: From Mount Darwin in Tasmania

Tektites can be black, brown, gray, white, or green. They often have irregular, intricate shapes or resemble glassy pebbles. Most have numerous bubbles inside.


natural glass gemstone fulguritePictured above: Type I sand fulgurite | Image credit: Rama, CC-BY-SA-2.0

Fulgurite, or “fossilized lightning,” is fused silica coated in sand, formed from lightning strikes.

Depending on what the lightning hit, there are 4 main fulgurite classes:

  • Type I: From wet sand; Thin glass walls, almost entirely sand; 95-100 percent glass

  • Type II: From clay soil; Thicker glass walls; Up to 90 percent glass

  • Type III: From calcic sediment; Mostly calcium-carbonate-based cement called caliche; Up to 10 percent glass

  • Type IV: From rocks; Thicker glass walls; Up to 90 percent glass

Each type varies in appearance and size. They’re usually black or tan, but impurities can lend other colors. Colored fulgurites can also form when lightning strikes man-made objects.

Volcanic Glass

Besides obsidian, other notable volcanic glass types are:

  • Tachylite: Black or dark brown, resinous luster, resembles tar; Sometimes contains small olivine or feldspar crystals; Sideromelane: Transparent, yellow-brown

  • Palagonite: Term for various products of volcanic glass alteration, either water and basalt melt or basaltic glass weathering; Often yellow-orange to brown; Gel-palagonite: Colorless, transparent, smooth; Fibro-palagonite - Translucent, fibrous or granular, birefringent

  • Macusanite: Usually yellow-green, transparent, and pebble-like with andalusite and sillimanite phenocrysts; Earliest specimens from Macusani basin, Peru

  • Pele’s Hair: Golden-yellow, resembles straw or hair; Forms when cooled lava stretches into thin fibers, often carried away by wind

  • Pele’s Tears: Jet black, tear-like drops, usually on end of Pele’s Hair (pictured below)

  • Limu o Pele (Pele’s Seaweed): Brownish-green to near-colorless, shattered flakes and thin sheets resembling seaweed

The last three are named after Pele, the Hawaiian goddess of volcanoes.

natural glass pele's tears gemstonePictured above: Pele's Tears | Image credit: James St. John, Flickr, CC-BY-SA-2.0

Natural Glass History

Although humans started making glass around 4,000 years ago, uses of natural glass go way back. People made obsidian tools during the Stone Age. The first known mirrors from around 4,000 BC were polished obsidian!

But glass in nature was around long before humans. The oldest known batch of tektites dates back to when non-avian dinosaurs went extinct, likely formed via the meteorite impact behind that extinction.

The earliest tektite tools are dated between 4,000-6,000 BC. Tektites were also used for good luck around 500 BC. The first written reference of tektites dating to 950 AD came from Liu Sun, who called them Lei-gong-mo, Chinese for “inkstone of the thundergod.”

natural glass obsidian gemstone healing pendantPictured above: Obsidian pendant

Natural Glass Healing Properties

Natural glass gems can be used as powerful healing stones. With the array of colors, glass gemstones can be chakra stones for opening any chakra.

Dark glass gems like obsidian or Pele’s tears are commonly used for clairvoyance and divination. Fulgurites’ lightning-strike origins are said to invigorate the spirit and boost circulation.

natural glass moldavite gemstone ringPictured above: Moldavite ring

Natural Glass Gemstone Properties

Natural glass gemstones aren’t graded like other gems, but we’ll highlight the grading properties that can influence their value.

  • Color: Obsidians, tektites, and Libyan desert glass with rarer colors are more valuable. Iridescence can also add value.

  • Cut: Generally, high-quality faceted cuts are most valuable, except with chatoyant obsidian that must be cut as cabochons.

  • Transparency: Higher transparency means higher value in all natural glass.

  • Size: Size is often number-one for tektite value, with larger sizes commanding higher prices. Size is somewhat important for fulgurite value.

  • Rarity: Rarer natural glasses like tektites are more valuable than common ones like obsidian.

Natural Glass Formation & Sources

Natural glass can form in a few ways:

  • Volcanic Activity: Magma or lava rapidly cools into glass (Volcanic glass, obsidian)

  • Meteorite Impact: Meteorite hits Earth, causing materials to rapidly melt, fly into the air, then rapidly cool into glass as they falls back to Earth (Tektites)

  • Weather Events: Lightning strikes sand or rock, melting it and fusing the silica into glass (Fulgurites)

Some stones like obsidian are considered natural glass lava rocks.

Some animals like the Hexactinellid sponge, or “glass sponge,” have amorphous, silica-based tissues (spicules). Some scientists call it a glass-based skeleton — which remains after the sponge dies (like coral) — but others say it’s only glass-like.

Scientists discovered another organic glass in 2015: a protective “bioglass” created by the tiny sea creatures tardigrades (a.k.a. water bears) when they’re dehydrated. The glass holds them together until their cells are rehydrated.

Mining Locations

Where is natural glass found? Natural glass is found all over the world, with certain types specific to geological locations.

Volcanic glass types like obsidian are found in volcanic regions, with significant deposits worldwide. Pele’s Hair and Pele’s Tears are also found in volcanic regions, notably in Nicaragua, Italy, Ethiopia, and Iceland.

For tektite locations, check out our Tektite Info Guide.

natural glass snowflake obsidian gemstone earrings

Pictured above: Snowflake obsidian earrings

Natural Glass Price & Value

Natural glass stone prices vary by individual stone, though they’re pricier than made-made glass gems.

Obsidian is the most affordable, typically costing $2-$5 per pound.

You can see the price ranges of various tektites in the info guide linked above. Ivorites and Uruguaites are usually priciest, while Zhamanshinites and Philippinites are usually most affordable.

Fulgurites range broadly, from around $5 to upwards of $5,000.

Natural Glass Care and Maintenance

Last up is gemstone care. Most natural glass is safe to touch, but always wear gloves when handling Pele’s Hair!

With mid-range hardness, we recommend protective settings on natural glass gemstone jewelry, particularly rings. Clean the stones with mild soap, warm water, and a soft toothbrush.

natural glass rainbow obsidian gemstones heart parcelPictured above: Rainbow obsidian

Open a Window of Opportunities with Natural Glass Gems!

If you love gemstones for their natural beauty, natural glass gemstones are a great way to expand your horizons into what Earth and the cosmos can offer. You’ve got plenty of unique shapes and colors to choose from, so what are you waiting for?

Buy natural glass gemstones like obsidian or tektites like Darwin glass, moldavite, and more today!



















  • 莫氏硬度:5-6

  • 顏色:通常是黃色、藍色或藍綠色;幾乎可以是任何顏色,具體取決於雜質

  • 晶體結構:無(無定形)

  • 光澤: 玻璃光澤

  • 透明度: 透明到不透明

  • 折射率:1.46-1.69(因類型而異)

  • 密度:2.2-3.0(因類型而異)

  • 乳溝:無

  • 斷口: 貝殼狀

  • 條紋:白色

  • 發光: 無

  • 多色性:無

  • 雙折射:無

  • 色散:無

  • 光學效果: 黑曜石可能出現 Chatoyancy 和 iridescence







  • 氧化鐵:紅色和棕色

  • 長石或磁鐵礦納米顆粒:彩虹色、彩虹般的光澤

  • 被困氣泡:金色光澤

  • 徑向簇狀方英石晶體:雪花圖案

  • 定向石榴石納米棒:七彩彩虹條紋



天然玻璃隕石綠隕石寶石刻面上圖:Moldavite 寶石


tektite 玻璃的類型通常以發現它們的“散佈區域”命名,例如:

  • 捷克隕石:產自捷克的摩爾道河

  • 利比亞沙漠玻璃:來自利比亞沙漠

  • 澳大利亞石:來自澳大利亞

  • 象牙人:來自象牙海岸

  • 達爾文玻璃:產自塔斯馬尼亞的達爾文山



天然玻璃寶石電輝石上圖:I 型砂閃鋅礦 |圖片來源:拉瑪, CC-BY-SA-2.0


根據閃電擊中的對象,有 4 種主要的電輝石類:

  • I 型:來自濕沙;薄薄的玻璃牆,幾乎全是沙子; 95-100% 玻璃

  • II型:來自粘土;加厚玻璃牆;高達 90% 的玻璃

  • 類型 III : 來自鈣質沉積物;主要是碳酸鈣基水泥,稱為caliche;高達 10% 的玻璃

  • 類型 IV :來自岩石;加厚玻璃牆;高達 90% 的玻璃




  • Tachylite :黑色或深棕色,樹脂光澤,類似焦油;有時含有小橄欖石或長石晶體; sideromelane:透明,黃棕色

  • Palagonite :各種火山玻璃蝕變產物的術語,水和玄武岩熔體或玄武岩玻璃風化;通常是黃橙色到棕色;凝膠鈣鎂石:無色透明,光滑;纖維鈣鎂石 - 半透明、纖維狀或顆粒狀、雙折射

  • 馬庫桑石:通常呈黃綠色,透明,呈鵝卵石狀,伴有紅柱石矽線石斑晶;來自秘魯 Macusani 盆地的最早標本

  • 貝利的頭髮:金黃色,類似稻草或頭髮;當冷卻的熔岩伸展成細纖維時形成,通常被風帶走

  • 貝利的眼淚:烏黑的淚滴,通常在貝利的頭髮末端(如下圖)

  • Limu o Pele (Pele's Seaweed) :棕綠色至近無色、破碎的薄片和類似於海藻的薄片


天然玻璃貝利的眼淚寶石上圖:貝利的眼淚 |圖片來源:James St. John, Flickr CC-BY-SA-2.0


雖然人類大約在 4,000 年前就開始製造玻璃,但天然玻璃的使用可以追溯到很久以前。人們在石器時代製作黑曜石工具。公元前 4,000 年左右,已知的第一塊鏡子是用拋光的黑曜石製成的!


最早的隕石工具可追溯到公元前 4,000-6,000 年。公元前 500 年左右,隕石也被用於帶來好運。公元 950 年,關於隕石的第一個書面參考來自劉孫,他稱其為雷公墨,中文意思是“雷神的硯台”。




黑曜石或貝利之淚等深色玻璃寶石通常用於千里眼和占卜。 Fulgurites 的雷擊起源據說可以振奮精神並促進血液循環。




  • 顏色:黑曜石、隕石和利比亞沙漠玻璃的顏色越稀有,價值就越高。彩虹色也可以增加價值。

  • 切工:一般來說,高質量的刻面切工是最有價值的,除了chatoyant黑曜石必須切磨成凸圓形

  • 透明度:更高的透明度意味著所有天然玻璃的價值更高。

  • 尺寸:尺寸通常是鈦隕石價值的第一位,尺寸越大價格越高。尺寸對於電輝石的價值來說有些重要。

  • 稀有性:玻璃隕石等稀有天然玻璃比黑曜石等普通玻璃更有價值。



  • 火山活動:岩漿或熔岩迅速冷卻成玻璃(火山玻璃、黑曜石)

  • 隕石撞擊:隕石撞擊地球,導致物質迅速熔化,飛向空中,然後在落回地球時迅速冷卻成玻璃(隕石)

  • 天氣事件s:閃電擊中沙子或岩石,將其熔化並將二氧化矽熔化成玻璃(Fulgurites)


一些動物,如 Hexactinellid 海綿或“玻璃海綿”,具有無定形的二氧化矽基組織(針狀體)。一些科學家稱它為玻璃骨架——在海綿死亡後仍然存在(如珊瑚)——但其他人則說它只是玻璃狀的。

科學家們在 2015 年發現了另一種有機玻璃:一種保護性“生物玻璃”,由微小的海洋生物緩步動物(又名水熊)在脫水時產生。玻璃將它們固定在一起,直到它們的細胞重新水化。









黑曜石是最實惠的,通常每磅 2-5 美元。


Fulgurites 範圍廣泛,從大約 5 美元到 5,000 美元以上。








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