Blue John
Embed This Widget
Add the script tag and a data attribute to embed this widget.
Embed via iframe for maximum compatibility.
<iframe src="https://gemfyi.com/iframe/entity/blue-john/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://gemfyi.com/entity/blue-john/Add a dynamic SVG badge to your README or docs.
[](https://gemfyi.com/entity/blue-john/)Use the native HTML custom element.
Add one script tag to your page:
<div data-gemfyi="entity" data-slug="blue-john"></div>
<script src="https://cdn.jsdelivr.net/npm/gemfyi-embed@1/dist/embed.min.js" defer></script>
Embed as an iframe:
<iframe src="https://gemfyi.com/iframe/entity/blue-john/?style=modern&theme=light" width="420" height="400" frameborder="0" loading="lazy" style="border:0;border-radius:10px;max-width:100%"></iframe>
Paste the URL in WordPress, Medium, or Ghost:
https://gemfyi.com/zh-hans/gems/blue-john/
Shields.io-compatible SVG badge:
Web Component:
<gemfyi-entity slug="blue-john"></gemfyi-entity>
<script src="https://cdn.jsdelivr.net/npm/gemfyi-embed@1/dist/embed.min.js" defer></script>
Physical & Optical Properties
Category
Semi-Precious Gems
Mohs Hardness
4.0
Specific Gravity
3.0 – 3.25
Refractive Index
1.432 – 1.436
Crystal System
Isometric
Luster
Vitreous
Cleavage
Perfect
Color
various
Mohs Hardness
| Mohs | Reference mineral | Blue John |
|---|---|---|
| 1 | Talc | |
| 2 | Gypsum | |
| 3 | Calcite | |
| 4 | Fluorite | ● |
| 5 | Apatite | |
| 6 | Orthoclase | |
| 7 | Quartz | |
| 8 | Topaz | |
| 9 | Corundum | |
| 10 | Diamond |
Crystal System
Value & Market
Price Tier
Budget (< $50/ct)
Where to Buy Blue John
Blue Nile
Fine jewelry retailer
James Allen
Gemstone jewelry
Brilliant Earth
Ethically sourced gems
Amazon
Wide selection
Links may earn a commission at no extra cost to you.
Treatments
4Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
3.00 to 3.25Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
PerfectHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
1.432 to 1.436Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
IsotropicUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Banded white/purpleGemdat.org, Management Team (2012)
Transparent,TranslucentArthur Thomas, Gemstones (2009)
VitreousArthur Thomas, Gemstones (2009)
IsometricHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Cubic, massiveArthur Thomas, Gemstones (2009)
Blue John information at mindat.org
UK
[www.thamesvalleyminerals.com]
Fluorite: The Collector's Choice. Extra Lapis English No. 9
About Blue John
蓝约翰是一种具有独特紫色和白色带状花纹的萤石变种，仅产于英国德比郡凯斯尔顿村附近的蓝约翰洞穴。这种珍贵的地方性宝石自罗马时代起便备受珍视，英国乔治王朝时期的工匠将其制成装饰花瓶和各种精美工艺品。由于产量极为有限，蓝约翰已成为英国矿物遗产的重要组成部分。
On this page
Jewelry Use
Durability
3/10
Science FYI Family
Frequently Asked Questions
What is Blue John?
蓝约翰是一种具有独特紫色和白色带状花纹的萤石变种，仅产于英国德比郡凯斯尔顿村附近的蓝约翰洞穴。这种珍贵的地方性宝石自罗马时代起便备受珍视，英国乔治王朝时期的工匠将其制成装饰花瓶和各种精美工艺品。由于产量极为有限，蓝约翰已成为英国矿物遗产的重要组成部分。
What is the hardness of Blue John?
Blue John has a Mohs hardness of 4.0, making it relatively soft for use in jewelry.
What color is Blue John?
Blue John is primarily Various.
How much does Blue John cost?
Blue John falls into the Budget (< $50/ct) price range. Prices vary based on color, clarity, cut, and origin.
What is the crystal system of Blue John?
Blue John belongs to the Isometric crystal system.