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Behoite mineral

Behoite (IMA 1969-031) is an IMA-accepted beryllium hydroxide mineral, the natural orthorhombic beta-Be(OH)2 polymorph, with IMA September 2026 Master List formula Be(OH)2. Described by Ehlmann and Mitchell (1970) from the Rode Ranch rare-earth pegmatite, Llano County, Texas, USA (and also recognized in hydrated Vitro-tuff at Honeycomb Hills, Juab County, Utah, USA), where it occurs as colorless, pseudo-octahedral crystals ({011} dome with {110} prism faces) in white to tan powdery alteration rinds replacing brown gadolinite in association with tengerite, bastnaesite, albite, and quartz. Semiquantitative spectrographic analysis by A. S. McCreath and Son (Table 1, p. 4) shows Be as the major cation with Si (1–10%), Fe (0.3–3%), and minor/trace elements. The authors observed minor clay impurities and did not establish silicon or iron as essential behoite constituents. Orthorhombic (space group P212121), with a = 4.64(2) Å, b = 7.05(2) Å, c = 4.55(3) Å, Z = 4, measured natural specific gravity SGmeas = 1.92 ± 0.01 (cited synthetic measured density 1.924), Mohs hardness ~4, and biaxial (–) optics with alpha = 1.533(3), beta = 1.544(3), gamma = 1.548(3), and 2V = 82°.

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Identifiers & Classification

System Identifier Label
IMA IMA:1969-031 Behoite

Microbial & Biochemical Mechanisms (1)

Behoite other Abiotic two-step DTA thermal decomposi

Abiotic two-step DTA thermal decomposition of behoite

other

Two-step thermal decomposition of natural orthorhombic beta-Be(OH)2 (behoite) recorded by unplotted DuPont 900 differential thermal analysis (DTA, 20 °C/min in air), described in the p. 7 thermal-data section as a two-step endothermic reaction with inflections beginning near 265 °C and 290 °C and peaking at 310 °C (whereas the p. 1 abstract refers to the 310 °C DTA feature as an exothermic peak; reaction products were not separately characterized in the DTA paragraph).

Experimental Context & Analytical Limits:
Abiotic laboratory differential thermal analysis (DTA) on Rode Ranch behoite using a DuPont 900 thermal analyzer in air at 20 °C/min; no microbial, enzymatic, or bioleaching mechanism was tested or reported in Ehlmann and Mitchell (1970).
Curated Evidence Points:
In the unplotted differential thermal analysis (DTA) discussion on p. 7, Rode Ranch behoite heated on a DuPont 900 thermal analyzer in air at 20 °C/min is described as undergoing a two-step endothermic reaction beginning at approximately 265 °C and 290 °C and peaking at 310 °C, whereas the p. 1 abstract refers to an exothermic peak at 310 °C (pp. 1, 7).

Sources & References

  1. ima_2026_09: IMA-CNMNC (Pasero M., 2026), The New IMA List of Minerals – A Work in Progress (Updated: September 2026), PDF p. 23, Behoite row: status A, IMA 1969-031, formula Be(OH)2, reference Ehlmann A.J., Mitchell R.S. (1970) American Mineralogist 55, 1-9.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-24)
  2. ehlmann_1970_behoite: Ehlmann AJ and Mitchell RS (1970), Behoite, beta-Be(OH)2, from the Rode Ranch pegmatite, Llano County, Texas, American Mineralogist 55:1-9.
    https://www.rruff.net/doclib/am/vol55/AM55_1.pdf (accessed 2026-10-24)

Curation History

Timestamp Curator Action Summary
2026-10-24T07:30:00Z antigravity CREATE Created mineral record for Behoite (IMA:1969-031) from the IMA September 2026 Master List and the primary type-description paper by Ehlmann and Mitchell (1970) in American Mineralogist 55:1-9, including its abiotic DTA dehydroxylation mechanism.
2026-10-24T10:45:00Z antigravity EDIT Resolved CMM120-F4 (issue #838) by replacing the unsupported wet-chemical oxide list and Dcalc = 1.94 g/cm3 with the Table 1 McCreath semiquantitative spectrographic analysis and measured densities (natural 1.92 ± 0.01, cited synthetic 1.924), correcting {011} dome morphology, removing the nonexistent Fig. 4 citation while noting the p. 1 abstract vs p. 7 DTA exothermic/endothermic discrepancy, and simplifying sources[1].title to a concise bibliographic citation.
2026-10-24T11:27:00Z antigravity EDIT Applied reviewed conservative correction for CMM120-F4 (issue #838): removed unsupported quartz/steel-needle contamination attribution from description while retaining the observed minor clay impurity limitation on Si and Fe.

Record source: data/records/behoite.yaml