| IGSN | Sample Type | Notes | Location | Number Thin Sections | Storage Location |
|---|---|---|---|---|---|
| GRD039YS0 | Brookite | Brookite var. Arkansite. Several large crystals of black splendant brookite(up to 3/8 inch) on cavernous matrix of quartz. The latter contains numerals small individuals of brookite. From collection of John Sinkankas | Arkansas | 0 | Ritter 154, 12 C |