## Part 1: Making the LA-TGS Solution

### Raw Materials You Need
- Reagent grade glycine (you have this)
- Concentrated sulfuric acid, battery grade (you have this)
- L-alanine powder (food grade or reagent grade, cheap and widely available)
- Deionized or distilled water

### Synthesis

Prepare TGS by taking glycine and concentrated sulfuric acid in the molar ratio of 3:1. Dilute the required volume of concentrated sulfuric acid with water first, then slowly dissolve the calculated amount of glycine into the diluted acid while continuously stirring.

**The critical safety and chemistry point:** always add acid to water first, then glycine to that diluted acid — never add water to concentrated acid directly. The reaction is exothermic.

Keep the solution temperature below 60°C throughout to avoid chemical decomposition of glycine. 55°C is the safe working temperature. Too hot and you start getting off-products.

**Specific quantities for a small batch** (targeting ~200ml of saturated solution at 35°C, enough for several gel tubes):

The solubility of TGS at 35°C is approximately 425g/L. For 200ml you need ~85g TGS. TGS molecular weight is 323g/mol, glycine is 75g/mol, H₂SO₄ is 98g/mol. At 3:1 molar ratio: 3 × 75 = 225g glycine per 98g acid.

So for 85g TGS: roughly **59g glycine** and **26g sulfuric acid** (about 14ml of concentrated 96% H₂SO₄) dissolved into ~150ml water, then topped up.

**Adding L-Alanine:**

Add 7 mol% of L-alanine to the TGS solution. 7 mol% relative to TGS means for every mole of TGS you're growing, you add 0.07 moles of L-alanine (MW 89g/mol). For your small batch of ~0.26 mol TGS, that's about **1.6g of L-alanine** added directly to the solution. Add it after the glycine and acid have fully reacted and the solution has cooled slightly to ~50°C.

Dissolve the glycine and sulfuric acid in deionized water, heat to 50°C to obtain the synthesized TGS salt, then dissolve the salt again in fresh distilled water and recrystallize by natural evaporation. Repeat this purification cycle two times before adding the L-alanine dopant to the final mother solution.

This double-recrystallization purification step is what separates good crystals from mediocre ones. Yes it takes time. Do it.

---

## Part 2: Making the Silica Gel

### What You Need
- Sodium silicate solution (waterglass — you already have this)
- Dilute sulfuric acid (you have battery grade — dilute it significantly, see below)
- pH indicator paper (wide range, 1–10)
- Your 25 or 50ml conical glass centrifuge tubes

### Gel Preparation

Waterglass readily transforms into silica gel upon acidification. Adding acid to sodium silicate triggers partial neutralization of Si–O⁻Na⁺ ion pairs, forming reactive silanol Si–OH groups, which then connect by forming Si–O–Si bridges into a 3D gel network.

The procedure is:

1. **Dilute your sulfuric acid first** to approximately 1N (about 1 mol/L, which is roughly a 5% solution by weight from concentrated battery acid). This gives you fine control — concentrated acid will overshoot your target pH violently and you'll waste a tube.

2. **Dilute your waterglass** — if it's the thick hardware-store type, dilute it approximately 1:1 with distilled water. You want a pourable, somewhat viscous liquid, not a syrup.

3. **Add the dilute acid dropwise to the waterglass** while stirring, checking pH with indicator strips after each addition. Gelation time increases with increasing pH — a more acidic gel sets faster. You want to stop at **pH 3.5 to 4.0** — this gives you safety margin above the pH 2.5 TGS/DGS boundary, accounts for the locally acidic TGS solution that will diffuse down into the gel, and still gives a gel that sets within a few hours rather than days.

4. **Pour the liquid sol immediately** into your clean conical centrifuge tubes, filling them to about **half to two-thirds full**. Work quickly — once acidified, the clock is running.

5. **Seal the tubes loosely** (Parafilm with a small hole, or just a piece of tissue paper over the top held with a rubber band) and leave undisturbed at room temperature. The gel will set firm within 2–6 hours depending on your exact pH and silicate concentration.

6. **Age the gel for 24–48 hours** before adding your TGS solution on top. A freshly set gel is still weak and syneresis (the gel contracting and weeping liquid) is more likely if you disturb it too soon.

---

## Part 3: Layering the TGS Solution and Growing

1. After purifying your LA-TGS twice by recrystallization, **prepare a moderately concentrated solution** — not fully supersaturated. Dissolve your LA-TGS salt in warm distilled water at ~45°C to get a clear solution, then let it cool to room temperature. It should be clear and slightly more concentrated than room-temperature saturation, but not so supersaturated that crystals immediately precipitate.

2. **Gently pipette or pour the LA-TGS solution on top of the set gel** in each tube, disturbing the gel surface as little as possible. The liquid-gel interface needs to stay sharp. Pour down the side of the tube rather than directly onto the gel surface. Add enough to give a **3–5cm column of solution** above the gel.

3. **Seal the tubes with Parafilm** (with a single small pinhole — you want extremely slow evaporation, not sealed completely). This slows evaporation to almost nothing and forces the crystal growth to be driven purely by diffusion of TGS into the gel rather than by surface evaporation, which is what gives you large, well-faceted single crystals.

4. **Leave at room temperature**, undisturbed, in a dust-free location out of direct vibration. A shelf inside a cabinet is ideal. Do not put near an air vent.

5. **Check weekly** with a magnifying glass or loupe. Nucleation typically appears within 1–3 weeks as tiny glints of crystal forming at or just below the gel surface, or within the gel at a diffusion front a few mm below the liquid-gel boundary.

---

## Part 4: Extracting and Evaluating Seeds

Once crystals reach 3–8mm in their largest dimension (2–4 weeks typically), extract them:

1. **Dissolve the gel** by decanting the supernatant solution and flooding the tube with dilute sodium carbonate solution (washing soda, ~5% in water). The silica gel dissolves within a few hours to overnight. Do not use NaOH — it's too aggressive and may damage the TGS crystal surface (TGS is soluble in water and sensitive to strong base).

2. **Rinse gently** with a small amount of cold distilled water and immediately transfer to a desiccator. TGS is hygroscopic — surfaces will absorb moisture and become hazy if left in humid air.

3. **Identify the (010) face** using the crystal outline method from Preezant (superimpose on the face diagram, Fig. 14 in their paper). The (010) face on LA-TGS gel crystals will be more prominent than on pure TGS thanks to the L-alanine biasing growth along the b-direction.

4. **Select seeds** showing the largest, flattest (010) face, minimal inclusions, and good transparency. Small is fine — a 5×5mm seed with a clean (010) face is better than a large cloudy one.

---

## Practical Considerations

**pH is everything.** Buy pH indicator strips that cover at least pH 1–6. Check each tube before pouring. A single tube that gels at pH 2.3 instead of 3.5 will grow DGS crystals instead of TGS and you won't know until weeks later.

**Glycine oxidation:** To avoid oxidation of glycine, maintain solution temperature below 45°C during the recrystallization step. You can synthesize at 55°C but once you have your TGS salt, re-dissolving and evaporating should be done gently.

**Vibration is the enemy of gel growth.** The gel suppresses convection, which is the whole point — but mechanical vibration couples right through a gel. Don't put tubes on the same shelf as a stirring hotplate.

**Run multiple tubes in parallel.** Gel growth has inherent variability in nucleation. Run 6–10 tubes simultaneously. Half may produce polycrystalline junk, a few will give you one or two excellent single crystals. That's normal.

**Don't re-use the supernatant solution** from a failed tube directly — it will have sodium from the gel dissolution. Start fresh for each batch of tubes.

**Thread vs. platform for the S-R stage:** Once you have your gel-grown LA-TGS seed with an identified (010) face, mount it at the bottom of your conical S-R tube with the (010) face perpendicular to the growth direction (i.e., facing up the tube). A small platform of PTFE or HDPE with a slot cut to hold the crystal by its edges — rather than a thread through the crystal — gives far better orientation control and avoids the secondary nucleation on thread problem the Preezants struggled with.


##################### GEMINI TRIES #############################################

Combining the sodium metasilicate gel method to grow perfect, defect-free seed crystals with your specific battery-acid TGS recipe is an excellent, professional-level approach.

By using your battery acid (sulfuric acid) to set the silica gel, you actually gain a massive advantage over standard lab protocols: you aren't introducing any foreign chemicals. Traditional methods use acetic acid to set the gel, but by using sulfuric acid, the only ions in your jar are silica, sodium, sulfate, and glycine. This keeps your TGS incredibly pure.

Here is the complete, step-by-step master recipe, perfectly scaled so you end up with 100 mL of TGS supernatant sitting on top of a pristine silica gel base.

Part 1: Make the 100 mL TGS Supernatant

You will make this exactly as calculated before. Because we are using the gel method, you want this solution to be at room temperature when you finally pour it, so you can make it while waiting for your gel to set.

The Masses & Volumes:

Distilled / Deionized Water: 84.5 mL

Glycine: 20.9 g

Battery Acid (37%): 19.5 mL

The Steps:

Warm the 84.5 mL of distilled water to about 45°C.

Dissolve the 20.9 g of glycine into the water completely.

(Wearing gloves and goggles) Slowly add the 19.5 mL of battery acid while stirring.

Let it react and stir for 1 to 2 hours.

Take it off the heat, let it cool completely to room temperature, and filter it through a coffee filter into a clean, sealed bottle. Set it aside.

Part 2: Prepare the Silica Gel Base

You want the gel to fill the bottom 1 to 2 inches of your growth jars (or a large glass test tube). We will make a 50 mL batch of gel.

The Masses & Volumes:

Sodium Metasilicate Powder (often sold as "Waterglass" powder): ~5.0 grams

Distilled Water: 50.0 mL

Battery Acid (37%): Roughly 2 to 5 mL (You will add this drop-by-drop based on pH, rather than an exact measurement).

The Steps:

Dissolve the Silica: Add the 5.0 g of sodium metasilicate to the 50 mL of distilled water. Stir vigorously until it is fully dissolved. (Note: This solution is highly alkaline/basic).

Acidify to Form the Gel: To make the silica polymerize into a gel, you must lower the pH. Furthermore, TGS requires a specifically acidic environment to prevent a useless mutant crystal (Diglycine Sulfate) from forming. You want a pH of roughly 3.0 to 3.5.

Titration: Slowly add your 37% battery acid to the silica solution one drop at a time while stirring continuously. Check the liquid frequently with pH test strips.

Pour Quickly: Once the pH hits roughly 3.0, the solution is "activated." Stop adding acid. Pour this liquid immediately into your crystal growing jar(s).

Let it Set: Cover the jar to prevent dust from getting in, and place it somewhere totally undisturbed. Depending on exact room temperature and pH, it will take anywhere from 24 to 72 hours to fully polymerize. You will know it is ready when you tilt the jar and it doesn't flow—it will look like a stiff, perfectly clear Jell-O.

Part 3: The Gel Growth Process

Now you bring the two parts together to grow your flawless seed crystals.

Add the Supernatant: Uncover your jar of set gel. Take your 100 mL of room-temperature TGS solution and pour it very gently over the top of the gel.

Pro-Tip: Pour the liquid down a glass stirring rod or slowly down the inside wall of the jar so the impact doesn't physically break or gouge the soft gel surface.

Controlled Evaporation: Cover the jar with plastic wrap and poke 3 or 4 tiny pinholes in the top. Place it in a quiet place with stable room temperature.

The Physics of the Growth: As water very slowly evaporates out of the top over the next few weeks, the TGS solution becomes supersaturated. The TGS molecules will diffuse downward into the microscopic pores of the silica gel. Because the gel acts as a physical cage that entirely stops water currents and convection, the TGS cannot crash out into a bunch of messy, clumped polycrystals.

Harvesting: Instead, you will see 1 to 3 distinct, highly faceted, transparent crystals nucleate suspended inside the top layer of the gel. Let them grow until they are a few millimeters wide.

Extraction: Once they are a good size, reach in with a spoon and scoop out the gel containing the crystal. Run it under cool water—the silica gel is incredibly fragile and will easily wash away, leaving you with an absolutely pristine, stress-free TGS seed crystal in your hand.

You can then take this perfect seed, tie it to a nylon thread, and suspend it in the Preezant slow-cooling setup you linked to grow your massive, accelerator-grade final crystal!

## 40% silicate waterglass #############################################

If you are starting with a 40% liquid solution of sodium metasilicate (often sold as liquid "waterglass"), that actually makes your life a bit easier! The dry powder can sometimes clump up or take a while to dissolve, whereas the liquid solution will mix into your water instantly.

Since the liquid is 40% sodium metasilicate and 60% water by weight, we just need to adjust the math so you still end up with exactly 5.0 grams of the active silica compound in your 50 mL gel base.

Here is the adjusted math and procedure for the gel base:

1. The Adjusted Math

To get 5.0 grams of actual sodium metasilicate from a 40% solution:

5.0 g÷0.40=12.5 grams of your liquid solution
5.0 g÷0.40=12.5 grams of your liquid solution
.

Because liquid waterglass is quite dense and syrupy (usually around 1.4 g/mL), 12.5 grams works out to roughly 9 mL by volume. It is highly recommended to weigh it (12.5 g) rather than measure by volume, because the thick syrup sticks to measuring cylinders!

Those 12.5 grams of liquid will bring along 7.5 grams (or 7.5 mL) of water. Since we want our final mix to have 50 mL of water total, we just subtract that 7.5 mL from the water we add.

Your New Gel Base Recipe:
40% Sodium Metasilicate Solution: 12.5 grams (approx. 9 mL)
Distilled / Deionized Water: 42.5 mL
Battery Acid (37%): Still roughly 2 to 5 mL (added drop-by-drop based on pH).

2. The Updated Steps to Make the Gel

Dilute the Waterglass: Measure 42.5 mL of distilled water into a beaker. Weigh out your 12.5 g of the 40% sodium metasilicate solution and add it to the water. Stir it well so it is completely blended. (It is still highly alkaline, so keep wearing those gloves and goggles!)

Acidify: Just as before, you need to trigger the polymerization and set the TGS environment to a highly acidic pH of 3.0 to 3.5.

Titration: Take your 37% battery acid and add it to the silica mixture one drop at a time while stirring. Check the pH constantly with test strips or a pH meter.

Pour and Set: Once the pH hits roughly 3.0, stop adding acid. Immediately pour this 50 mL mixture into the bottom of your glass growing jar.

Wait for the Gel: Cover it to keep dust out and leave it completely undisturbed for 24 to 72 hours until it sets into a firm, clear, Jell-O-like solid.

3. Adding the TGS

Once the gel is set, nothing else changes!

You still make your 100 mL TGS solution exactly as we calculated before (84.5 mL water + 20.9 g glycine + 19.5 mL battery acid, reacted and cooled).

You still gently pour that 100 mL of room-temperature TGS over the back of a spoon onto your set gel.

Cover it, poke a few pinholes, and let the magic of slow diffusion grow your perfect seed crystals!

### cheaper brand  https://www.ebay.com/itm/110975079944 ###

Yes, using "Sodium Silicate 37.5% Type N" (commonly sold as liquid waterglass or head gasket sealer) will absolutely work to form your silica gel, but there are a few important caveats regarding its purity when it comes to growing optical-grade crystals.

Here is a breakdown of what to expect if you use an automotive-grade Type N sodium silicate, and how to get the best results from it.

1. What "Type N" Means

"Type N" is an industry-standard classification for sodium silicate. It means the liquid has a specific weight ratio of silica to sodium oxide (specifically, 3.22 parts SiO2 SiO2 to 1 part Na2ONa2O).

This is actually excellent news for you. Type N is the exact standard ratio most chemistry labs use to make silica gels for crystal growth because it polymerizes beautifully and predictably when acidified.

2. The Purity Issue (Automotive vs. Lab Grade)

Because this product is meant to seal engine blocks and not grow precise optoelectronic crystals, it is "Technical Grade" rather than "Reagent Grade."

Trace Metals: It will likely contain microscopic trace impurities, such as iron, aluminum, or calcium. In crystal growth, trace metals can act as rogue "nucleation sites." Instead of getting 1 or 2 perfect, massive seed crystals, impurities might cause the TGS to crash out into dozens of tiny, clustered, unusable crystals.

Additives: You must check the specific brand you are buying. Some auto head gasket sealers contain particulate additives (like copper flakes, ceramic fibers, or dyes) to help plug mechanical leaks. Do not use it if it has visible particles or dyes. You want a product that is purely a thick, clear (or slightly cloudy/syrupy) liquid.

3. How to Make it Work (The "DIY Purification" Step)

If you use the auto-repair waterglass, you should add a purification step to your workflow to give your crystals the best chance of growing flawlessly.

Filter it before you acidify:
When you are making your 50 mL gel base, you will be mixing the heavy sodium silicate syrup with distilled water.

Mix your waterglass and distilled water thoroughly.

Before you add any battery acid, pour this alkaline water/silica mixture through a fine coffee filter or a stack of two paper filters.

This will catch any undissolved silicates, dust, or microscopic automotive additives that could ruin your crystal's clarity.

Then, proceed to titrate it with your battery acid drop-by-drop until you hit the pH 3.0–3.5 mark.

4. A Tiny Adjustment to the Math

Because this product is 37.5% concentration (instead of the 40% we calculated previously), you just need a tiny bit more of it to reach the 5.0 grams of active silica required for your 50 mL gel bed.

New Math: 
5.0 g÷0.375=13.3 grams
5.0 g÷0.375=13.3 grams
 of the liquid Type N waterglass.

By volume, this is roughly 9.5 mL.

Because it brings about 8.3 mL of water with it, you will mix it with 41.7 mL of distilled water to reach your 50 mL total before you start adding your acid.

The Verdict: As long as it is a clear liquid without fibrous or metallic additives, automotive Type N waterglass is a fantastic, highly accessible substitute. By filtering the diluted mixture before you set the gel, you can easily bridge the gap between "garage chemistry" and precision material science!

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https://www.ebay.com/itm/253827134079 - $9 Pack of 80 pH Strips, pH Range 0.5 - 5.0, 80 Strips, Great for Kombucha & Kefir
https://www.ebay.com/itm/171393161009 - $5 1 Pack / 80 strips of pH 0.5-5.0 Special Indicator Paper test Lab Water Soil (bought)
https://www.ebay.com/itm/162199772085 - $11 Sodium Silicate / 4 Ounce Bottle / 99.9% Pure Reagent Grade / 41% Solution / USA (bought)
https://www.walmart.com/ip/BulkSupplements-L-Alanine-Powder-1g-per-Serving-100-Grams-3-5-oz-100-Servings/648280734 $12 L-Alanine 100g
https://www.ebay.com/itm/194468225976 - $12 L-Alanine 100g

### summary 37% silicate ###
To produce 50 mL of silica gel and 100 mL of TGS supernatant for crystal growth, follow these precise steps.

Part 1: The Silica Gel Base (50 mL)

Objective: Polymerize silica to create a convection-free environment.

Preparation: Mix 13.3g of 37.5% Sodium Silicate (Type N) with 41.7 mL of distilled water.

Note: Type N ratio is 
≈3.22SiO2:1Na2O
≈3.22SiO@:1Na2O molar.

Filter: Pass the mixture through a high-quality coffee filter to remove any potential industrial particulates.

Acidify: While stirring constantly, add 37% Battery Acid drop-by-drop until the pH reaches 3.0–3.5.

Note: This neutralization sets the gel and ensures the sulfate environment needed for TGS.

Set: Pour into your growth container and allow it to solidify (24–72 hours).

Part 2: The TGS Supernatant (100 mL)

Objective: Create a saturated nutrient solution for the gel-trapped seeds.

Dissolve: Mix 20.9g of Glycine into 84.5 mL of distilled water, warmed to 45°C.

Molar Ratio Note: Use 3 parts Glycine to 1 part Sulfuric Acid (
3C2H5NO2+H2SO4→(NH2CH2COOH)3⋅H2SO4
3C2H5NO2+H2SO4→(NH2CH2COOH)3⋅H2SO4

React: Slowly add 19.5 mL of 37% Battery Acid to the glycine solution. Stir for 2 hours.

Cool & Filter: Allow the solution to reach room temperature. Filter it to ensure zero debris.

Part 3: Growth Initiation

Combine: Gently pour the 100 mL TGS solution over the set silica gel using a glass rod to prevent surface cratering.

Seal: Cover the jar with plastic wrap, poke 3–4 tiny pinholes for controlled evaporation, and place in a vibration-free, temperature-stable location.

Harvest: Once seed crystals (2–3mm) appear within the top layer of the gel, extract them and wash away the gel with distilled water.

### 41% silicate ################3
Of course. Using a 99.9% pure, 41% reagent-grade sodium silicate solution is the ideal starting material. This eliminates the need for pre-filtering and ensures maximum clarity in your final gel.

Here are the adjusted, concise steps.

12.2g of your 41% Sodium Silicate solution
42.8 mL of distilled water
37% Battery Acid drop-by-drop until the solution's pH reaches 3.0–3.5.


Part 1: The Silica Gel Base (50 mL)

Objective: Polymerize a high-purity silica matrix for defect-free nucleation.

Preparation: In a clean beaker, mix 12.2g of your 41% Sodium Silicate solution with 42.8 mL of distilled water.

Note: Using reagent grade material means pre-filtering is not required.

Acidify: While stirring, add 37% Battery Acid drop-by-drop until the solution's pH reaches 3.0–3.5.

Note: This specific pH window is critical for TGS formation over other variants.

Set: Immediately pour the mixture into your crystal growing jar. Cover and let it set undisturbed into a firm, clear gel (24–72 hours).

Part 2: The TGS (or LA-TGS) Supernatant (100 mL)

20.9g of Glycine
84.5 mL of distilled water
19.5 mL of 37% Battery Acid
0.6g of L-alanine powder (7 mol% L-alanine doping level relative to the ~30g of TGS synthesized.)


Objective: Create the saturated TGS nutrient solution.

Dissolve: Mix 20.9g of Glycine and 0.6g of L-alanine into 84.5 mL of distilled water warmed to ~45°C.

Molar Ratio Note: This maintains the crucial 3:1 molar ratio of Glycine to Sulfuric Acid.

React: While stirring, slowly add 19.5 mL of 37% Battery Acid.

Cool: Allow the solution to fully react and cool to room temperature, then filter it to remove any microscopic dust.

Part 3: Growth Initiation

Combine: Gently pour the 100 mL of room-temperature TGS solution onto the surface of the fully set silica gel.

Seal & Wait: Cover the jar with plastic wrap and poke 3–4 pinholes to allow for very slow evaporation. Place in a stable, vibration-free environment.

Harvest: In a few weeks, perfect seed crystals will form inside the top layer of the gel. Scoop them out and gently wash away the gel with cool, distilled water to retrieve them.

#################CORRECTED CLAUDE VERSION with 41% and l-alanine and 35.5% battery acid ####################
# LA-TGS Gel Seed Crystal Growth — Final Procedure

# Materials
30.6 g Glycine (0.408 mol 3 parts)
29.7 mL Battery H₂SO₄ (SG 1.265, 35.5%) (0.136 mol 1 part)
0.95 g L-alanine (0.0107 mol 7 mol% of TGS)
84.5 mL Distilled water

12.2g Sodium silicate solution (41%)
42.8 mL Distilled water
Battery H₂SO₄ (SG 1.265, 35.5%) pre-diluted 1:10 titrated to pH 3.0–3.5


---

## Part 1: Silica Gel Base (~50 mL, fills 6–8 tubes)

| Material | Amount |
|---|---|
| Sodium silicate solution (41%) | 12.2 g |
| Distilled water | 42.8 mL |
| Battery H₂SO₄ (SG 1.265, 35.5%) pre-diluted 1:10 | titrated to pH 3.0–3.5 |

1. **Pre-dilute acid:** add 1 mL battery acid to 9 mL distilled water in a small glass vessel. This gives you fine control — undiluted acid will overshoot pH target in a single drop.

2. **Mix silicate:** combine 12.2g sodium silicate + 42.8 mL distilled water in a glass beaker. Stir until uniform and slightly viscous.

3. **Acidify:** add diluted acid dropwise while stirring, checking pH strip after every 5–10 drops. Slow to individual drops below pH 4.5. Stop firmly at **pH 3.0–3.5.** Below 2.5 you grow DGS not TGS.

This step requires *INTENSE* stirring so there are few local high concentration areas created. maybe use a drill and a stir tool, or a rotary tool and a stir tool.

4. **Pour immediately** into 6–8 clean 50 mL conical glass tubes, filling each to half volume (~25 mL). You have roughly 5–15 minutes before the sol becomes too viscous. Work quickly but don't splash — a smooth gel-liquid interface later depends on an undisturbed gel surface now.

5. **Cover** each tube loosely with Parafilm pierced with 2–3 small holes to prevent CO₂ buildup without drying the gel. Leave completely undisturbed on a vibration-free surface.

6. **Age:** allow 24–48 hours to set firm, then a further 24 hours aging. **Total minimum 48–72 hours before adding supernatant.** A freshly set gel is mechanically weak — adding liquid too soon causes syneresis and a disrupted interface.

---


## Part 2: LA-TGS Supernatant (100 mL)

| Compound | Amount | Moles | Molar ratio |
|---|---|---|---|
| Glycine | 30.6 g | 0.408 mol | 3 parts |
| Battery H₂SO₄ (SG 1.265, 35.5%) | 29.7 mL | 0.136 mol | 1 part |
| L-alanine | 0.95 g | 0.0107 mol | 7 mol% of TGS |
| Distilled water | 84.5 mL | — | solvent |

The 3:1 glycine:H₂SO₄ ratio is the stoichiometric requirement for TGS. Excess acid produces DGS contamination. L-alanine at 7 mol% relative to TGS locks the ferroelectric domain and biases crystal growth toward larger (010) faces.

1. **Warm** 84.5 mL distilled water to ~55°C in a glass beaker on your stirring hotplate.

2. **Dissolve glycine:** add 30.6g glycine to the warm water and stir until fully dissolved.

3. **Add acid slowly:** pour 29.7 mL battery acid in a thin slow stream while stirring continuously. The reaction is exothermic — temperature will rise noticeably. Keep stirring for 30–60 minutes at ~55°C until reaction is complete. Solution should be clear and colorless throughout.

4. **Add L-alanine:** remove from heat, cool to ~45°C, then add 0.95g L-alanine and stir until fully dissolved. Adding after the main reaction ensures the alanine doesn't interfere with TGS stoichiometry.

5. **Cool to room temperature.** If crystals begin to precipitate, gently rewarm to ~40°C until clear, then cool slowly again. A clear room-temperature solution means you're at or just below saturation — ideal for slow diffusion-driven gel growth.

6. **Filter** through Whatman #1 paper into a clean sealed glass vessel. Use within a few hours.

---

## Part 3: Combining and Growing

1. **Confirm gel readiness:** surface should be firm, smooth, and slightly shiny. If it wobbles or weeps liquid when the tube is tilted, wait another 24 hours.

2. **Layer the supernatant:** pipette or pour the room-temperature LA-TGS solution slowly down the inside wall of each tube — never directly onto the gel surface. Add enough for a **3–5 cm liquid column** above the gel. A sharp undisturbed gel-liquid interface is what controls nucleation depth and crystal quality.

3. **Seal:** cover each tube with Parafilm with **one needle-sized pinhole.** More holes accelerate surface evaporation, producing a polycrystalline crust at the interface rather than large single crystals growing into the gel body.

4. **Store** in an enclosed cabinet away from vibration, airflow, and direct light. Do not move or touch the tubes.

5. **Check weekly** with a loupe without picking the tubes up. Nucleation appears at 1–3 weeks as small glints at or just below the gel-liquid interface.

---

## Part 4: Harvest

1. **When crystals reach 5–10 mm** (typically 3–6 weeks), decant the liquid supernatant from each tube.

2. **Dissolve the gel chemically:** flood each tube with ~5% sodium carbonate solution (washing soda dissolved in distilled water). Leave undisturbed for 4–8 hours. The silica gel dissolves and crystals free themselves without mechanical stress. Do not poke, scrape, or try to pull crystals out — TGS cleaves easily and will crack.

3. **Rinse:** pour the dissolved gel liquid and freed crystals into a shallow glass dish. Rinse once briefly with a small amount of cold distilled water.

4. **Dry immediately:** transfer crystals to a desiccator within minutes of rinsing. TGS is hygroscopic and surfaces will haze rapidly in open air.

5. **Select seeds** under a loupe: look for full transparency, well-defined flat faces, and no internal striations or cloudy inclusions. Identify the (010) face using the Preezant face outline diagram (Fig. 14). L-alanine doping should make the (010) face visibly more prominent than on undoped crystals.

---

## Critical Numbers Summary

| Parameter | Value | Consequence of error |
|---|---|---|
| Glycine:H₂SO₄ molar ratio | 3:1 | Wrong ratio → DGS contamination |
| Gel pH | 3.0–3.5 | Below 2.5 → DGS not TGS |
| L-alanine | 7 mol% of TGS | Locks polar domain, widens (010) face |
| Gel age before use | 48–72 hrs minimum | Weak gel → syneresis, poor nucleation |
| Pinhole count | 1 | More → surface crust not bulk crystals |