Manganaxinite and Probable Margarosanite, Franklin Mine, Franklin, New Jersey

Contributed by: Chris Clemens
minID: H9G-ELG
Date: Apr 22nd, 2026
Locality: Parker shaft, Franklin Mine, Franklin, Sussex County, New Jersey, USA (See on Mindat)
Size: 4.7 x 3.2 x 9.8 cm
Weight: 197 g

Description:
Buff-colored piece of solid Axinite-(Mn) (aka manganaxinite), with minor willemite and a blue/white, fluorescent mineral that is likely margarosanite. The manganaxinite shows a deep red fluorescent response under shortwave UV, and a similar but less bright response under longwave UV. Manganaxinite is an uncommon member of the highly sought after Parker Shaft suite of rare fluorescent minerals from the famous Franklin Mine.

Margarosanite is another rare member of the Parker Shaft assemblage and is one of the most expensive and sought-after minerals from Franklin. As seen in the following close-up images, the suspected margarosanite appears as patches and dots of small plate-like crystals that fluoresce light blue under both shortwave and longwave UV.

Originally posted by Chris Clemens on Nature's Rainbows in 2018.

Afterglow after exposure to shortwave UV light.

Fluorescence under longwave UV light.

Normal light.

Normal light. Side 2.

Fluorescence under shortwave UV light. Side 2

Fluorescence under longwave UV light. Side 2.

Fluorescence under shortwave UV light. Closeup showing margarosanite.

Fluorescence under longwave UV light. Closeup showing margarosanite.

Normal light. Closeup showing margarosanite.

Summary of luminescence responses:

Axinite-(Mn) (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Red
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue