Terlingua-Type Calcite from an Uncommon Midwestern Location- Indianapolis, Indiana

Contributed by: Chris Clemens
Date: Apr 23rd, 2026
Locality: Indianapolis, Marion County, Indiana, USA (See on Mindat)
Size: 8.6 x 6.1 x 8.7 cm
Weight: 283 g

Description:
This is an unusual specimen of pink to white colored cleavage rhombs of calcite on limestone matrix, that show a Terlingua-type fluorescent response under UV. This piece was collected from one of the limestone quarries in the Indianapolis, Indiana, area and shows a classic Terlingua-type bright blue fluorescence with lasting phosphorescence under SW UV, and a bright pink response under LW UV. Under MW UV, the Terlingua-type area fluoresces a peach color with phosphorescence (not shown). Interestingly, under all wavelengths, this specimen simultaneously shows a distinct yellow response in a separate zone, and the Terlingua-like area cuts through the middle of the yellow zone of fluorescence. Under daylight, the Terlingua-type area has a distinct pink color, while the yellow fluorescing area is a yellowish-white color.

Originally posted by Chris Clemens on Nature's Rainbows in 2016.

Fluorescence under shortwave UV light.

Afterglow after exposure to shortwave UV light.

Fluorescence under longwave UV light.

Normal light.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue
• Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Blue
• Fluorescence under Longwave (365nm LED) UV light: Pink
• Fluorescence under Longwave (365nm LED) UV light: Yellow
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Yellow