step-cut ludlamite - Idaho
step-cut ludlamite - Idaho

Ludlamite Value, Price, and Jewelry Information


Ludlamite has a lovely green color, but cut stones are extremely rare. Large crystals of this phosphate mineral are known from only a few localities.

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Ludlamite has a lovely green color, but cut stones are extremely rare. Large crystals of this phosphate mineral are known from only a few localities.

step-cut ludlamite - Idaho
Freeform step-cut ludlamite, 1.35 cts, 9 x 6.7 mm, Blackbird Mine, Salmon, Lehmi Co., Idaho. © The Gem Trader. Used with permission.
ludlamites on quartz - Cornwall
Gemmy ludlamites on quartz, 7.2 x 4.7 x 4.7 cm, Wheal Jane, Baldhu, Gwennap area, Camborne - Redruth - St Day District, Cornwall, England, UK. © Rob Lavinsky, www.iRocks.com. Used with permission.

Does Ludlamite Make a Good Jewelry Stone?

In addition to beautiful color, ludlamites can show great brightness when faceted into gemstones. Unfortunately, this mineral occurs very rarely and even more rarely in cuttable sizes. They also have a hardness of only 3.5 and perfect cleavage. This makes ludlamite difficult to cut and impractical to wear as a jewelry stone. As a ring stone, it would need a protective setting and would be best reserved for occasional wear only. Use for earrings, pendants, and brooches would be more advisable.

However, you're more likely to find ludlamites in mineral collections, if at all, than in jewelry collections.

shield-cut ludlamite - Idaho
Shield-cut ludlamite, 0.26 cts, 5.2 x 2.7 mm, Blackbird Mine, Lemhi Co., Idaho. © The Gem Trader. Used with permission.

Distinguishing Ludlamites from Vivianites

Chemically similar, vivianite can occur in the same sources as ludlamite. When exposed to light, colorless and pale green vivianites can turn dark green as well as blue. Thus, some of these stones may look alike. Nevertheless, gemologists can distinguish them with some basic tests.

Ludlamites have a higher refractive index and specific gravity (1.650-1.697 and 3.19) than vivianites (1.569-1.675 and 2.64-2.68). Vivianites can also show dramatic pleochroic colors, but ludlamites have no pleochroism.

These gems also have different physical properties. Vivianites have a much lower hardness (1.5 to 2) than ludlamites. Vivianites also have a streak that can range from colorless to blue. Ludlamites have a pale, greenish white streak. However, scratch and streak testing are not recommended for finished gems.

Both gems are rarely cut, but vivianite is cut far less often than ludlamite.

Are There Any Synthetic or Treated Ludlamites?

There are no known lab-created ludlamites. These gems usually receive no treatments or enhancements.

Ludlamite Sources

The most celebrated source for gem-quality ludlamite, Blackbird Mine, Lemhi County, Idaho produces fine crystals up to a ½ inch across.

Other notable sources include the following:

  • United State: New Hampshire; South Dakota (crystalline masses to 12 inches in diameter with 7 mm crystals at Keystone).
  • Bolivia; Brazil; Cornwall, England; Hagendorf, Germany; Mexico.
ludlamites - Mexico
Cluster of ludlamites, 3.0 x 2.6 x 1.7 cm, San Antonio Mine, Santa Eulalia, Chihuahua, Mexico. © Rob Lavinsky, www.iRocks.com. Used with permission.

Ludlamite Gem Sizes

Transparent ludlamite material is always small. The potential may exist for cutting 5-10 carat gems, but most finished stones usually range from 1 to 2 carats or smaller.

How to Care for Ludlamites

Avoid cleaning ludlamites with mechanical cleaning systems, like steam and ultrasound. Clean these gemstones only with a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more care recommendations.

ludlamite - Idaho
Ludlamite: Idaho (~0.5). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Joel E. Arem, Ph.D., FGA

Dr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.

Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. joelarem.com


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