Gainesite is an exceptionally rare phosphate mineral discovered in complex granite pegmatites. It typically occurs as tiny, clear to milky-white tetragonal crystals often perched on matrix surfaces with other rare pegmatite minerals. Due to its scarcity and limited distribution, it is highly sought after by advanced systematic mineral collectors.
Is this gainesite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch gainesite with a known reference. Gainesite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Gainesite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Gainesite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish-white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: small, equant, pseudo-octahedral crystals.
Often confused with
Gainesite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside gainesite
Minerals reported to co-occur with gainesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Zr₂Be₂(PO₄)₄·H₂O
- Mohs hardness
- 4
- Density
- 2.85 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Small, Equant, Pseudo-octahedral Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find gainesite
Classic worldwide localities
- Tip Top mine, Custer, South Dakota, USA
Field-hunting tip
Look in granite pegmatites country — that is the host setting where gainesite typically forms. If you start seeing beryl, quartz, muscovite in float, you are in the right ground. Field specimens usually show a small, equant, pseudo-octahedral crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find gainesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
