the closeups and dime do help a lot… the crystals are very small, possibly beryl by hexagonal and prismatic habit, but much more likely to be tourmaline…
your suggestion of the triboelectric effect should very helpful…quartz is strongly negative but I think that it can be ruled out… great suggestion!.. nonetheless, taking the stones to an experienced jeweler or gemologist is still better yet.
basic triboelectric series for heavy minerals
The Journal of The Southern African Institute of Mining and Metallurgy VOLUME 110 REFEREED PAPER FEBRUARY 2010 77 ▲
Table II
Apparent triboelectric series for selected minerals based on inductive separation
Mineral name Recovery Charge acquired Comment
difference (%) (apparent)
Apatite -70.0 +++++++ Strong positive
Carbonates -40.2 ++++ Moderate positive
Monazite -38.4 ++++ Moderate positive
Titanomagnetite 0.4 . Neutral
Ilmenite 0.8 . Neutral
Rutile 2.0 . Neutral
Leucoxene 2.4 . Neutral
Magnetite/haematite 3.2 . Neutral
Spinels 3.4 . Neutral
Garnet 5.1 . Neutral
Staurolite 6.6 . Neutral
Altered ilmenite 13.3 - V. weak negative
Goethite 14.4 - V. weak negative
Zircon 20.4 – Weak negative
Epidote 20.9 – Weak negative
Tremolite 21.3 – Weak negative
Hydrous silicates 22.5 – Weak negative
Aluminosilicates 23.6 – Weak negative
Tourmaline 24.8 – Weak negative
Actinolite 26.0 – Weak negative
Pyroxene 29.7 — Weak negative
Titanite 39.1 ---- Moderate negative
Feldspar 43.0 ---- Moderate negative
Quartz 66.8 ------- Strong negative
None of the other minerals on the list are likely candidates…