| Mineral | ULEXITE |
| Chemistry | NaCaB 5 O 6 (OH) 6 ·5H 2 O |
| Class | Carbonates |
| Uses | an ore of boron and as mineral specimens. |
| Color | Colourlesswhite |
| Luster | Silky |
| Transparency | crystals are transparent to translucent. |
| CrystalSystem | Triclinic |
| CrystalHabits | include tufts of acicular crystals called cotton balls .Also as vein-like masses of parallel fibrous crystals. |
| Fracture | perfect in one direction. |
| Hardness | 2½ |
| Characteristics | similar borate minerals have an alkaline taste, while ulexite is tasteless. |
| Occurences | include several localities in California and Nevada, USA; Tarapaca, Chile and Kazakhstan. |
| Indicators | crystal habit, associations, locality, density, unique optical property, and hardness. |
| DensityNote | very low density |
| IMAStatus | Approved |
| Discovered | 1850 |
| CellParameters | a = 8.8b = 12.86c = 6.67 α=90.25°β=109.12°γ=105.1° |
| Ratio | a:b:c = 0.684 : 1 : 0.519 |
| OpticalType | Biaxial (+) |
| RI | n α =1.490 n β =1.510 n γ =1.520 |
| Birefringence | δ=0.030 |
| SurfaceRelief | Low |
| TypeLocality | Iquique Tamarugal Pampa Tarapacá Province Chile |
| Strunz | 5/H.14-10 5 : NitratesCarbonates & Borates H : Group borates. Planary groups [B2O5]4- to [B2O7]2- 14 : Ulexite series |
