Best Seller
Donghai, China · Since 2011
Fused Quartz Glass Tubes, Crucibles & Plates Manufactured to Your Drawing
Donghai Kemzo Quartz Products Co., Ltd. melts, forms and finishes high-purity quartz in Donghai County, Lianyungang – the region known as China's crystal capital for its natural quartz reserves. We supply laboratories, lighting and heater makers, semiconductor and photovoltaic processors, and distributors in more than 20 provinces and overseas markets with quartz parts that hold their shape, clarity and purity at temperatures where ordinary glass fails.
0+Production lines for tubes, rods, plates & crucibles
0%+Of annual output exported worldwide
0 YrsOEM / ODM experience making parts to drawing
0%Inquiry response rate, typically within 1 hour
Product Classification
Six core quartz families cover most buyer requirements. Every item can be supplied in stock sizes or cut, ground, polished and flame-worked to your dimensions and tolerances.
Lab · Lighting · Heating
Transparent Fused Quartz Glass Tubes
Clear tubes from capillary sizes to large furnace tubes, with controlled OD, wall thickness and straightness. Open-ended, sealed, flared or ground-joint ends available.
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Metallurgy · PV · Assay
Quartz Crucibles & Quartz Boats
Crucibles for melting precious metals and samples, plus wafer and sample boats with slot spacing made to your carrier. Low contamination and excellent thermal shock resistance.
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Optics · UV · Viewports
Quartz Plates, Discs & Windows
Square, round and custom-profile plates, sight windows and microscope slides. Double-side polished options for UV curing, furnace viewports and analytical instruments.
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Light Guides · Fixtures
Quartz Rods & Light Guide Rods
Solid rods with fire-polished or ground surfaces for light transmission, support pins and process fixtures. Cut-to-length with chamfered or polished ends.
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Semiconductor · Furnace
Diffusion & Ground-Joint Quartz Tubes
Process tubes for diffusion and oxidation furnaces, plus ground-mouth tubes with standard or custom tapers for vacuum and gas-tight lab assemblies.
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Raw Material · Lab
Quartz Sand, Quartz Wool & Labware
High-purity quartz sand graded by mesh size, quartz wool for filtration and catalyst support, and beakers, dishes and custom quartz ware for laboratories.
Explore rangeAbout Kemzo Quartz
Donghai Kemzo Quartz Products Co., Ltd. is a manufacturer and trading company specialising in the research, production and export of quartz products. Our plant sits in Lianyungang, Jiangsu, close to the natural quartz deposits that make Donghai one of the world's most important quartz processing clusters – giving us short supply chains for raw material and skilled local glass workers.
Our range spans high-purity quartz sand, transparent and opaque quartz tubes, diffusion tubes, ground-mouth tubes, quartz plates and slides, boats, crucibles, rods and light sticks, as well as quartz components for medical devices and scientific instruments. We have been recognised as a Jiangsu High Technology Enterprise and operate under an ISO 9001 quality management system.
Our working principle is simple: the client is the centre, and quality is the key.
- Business Type
- Manufacturer, Trading Company
- Founded
- 2011
- Factory Area
- 1,000 – 3,000 m²
- Annual Output
- US$10M – US$50M
- Team
- 11 – 50 employees
- Services
- OEM, ODM, Buyer Label
2011Established in Donghai
Factory & Quality Control
Quartz quality is decided long before final inspection. These are the control points our production team follows on every order, from raw sand to export crate.
Raw Material Screening
Natural quartz from the Donghai region is sorted, washed and checked for impurities before melting, because metallic contamination cannot be removed later.
Melting, Drawing & Forming
Over ten production lines draw tubes and rods or form plates and crucibles, with dimensions monitored throughout the run.
Annealing & Stress Relief
Flame-worked and ground parts are annealed to release internal stress, reducing the risk of cracking in thermal cycling.
Dimensional & Visual Inspection
OD, wall thickness, length and straightness are measured; bubbles, airlines and inclusions are checked under strong backlight.
Export-Grade Packing
Every piece is cushioned individually and crated for sea, air or express freight so it arrives ready to install.
Our Advantages
Why procurement teams in North America, Europe, East Asia and Oceania keep Kemzo on their approved supplier list.
Source-Region Material
SiO₂ up to 99.99%Located in Donghai's quartz cluster, we control raw material selection directly, giving consistent purity and stable pricing batch after batch.
Proven Thermal Performance
1100 °C continuousFused quartz's ultra-low expansion lets our tubes and crucibles survive rapid heating and quenching that would shatter borosilicate glass.
Made to Your Drawing
11 yrs OEM · ODMCutting, grinding, polishing, flame-working and sealing in-house. Send a drawing or sample and receive a feasibility check from our engineers.
Export-Ready Service
≤ 1h response · 7 IncotermsEnglish-speaking trade staff, flexible payment and Incoterms, and fragile-goods packing developed over years of international shipments.
Featured Quartz Series
From opaque milky quartz components to precision-ground parts and acid-resistant labware, these series reflect the custom work buyers request most often. Each is produced in small or volume batches with consistent dimensions.
Opaque & Milky QuartzHeat shields, washers, flanges
Precision-Ground PartsCut, ground & polished to drawing
Custom Quartz LabwareBeakers, dishes, cuvettes
Popular Quartz Products
Typical specifications are listed for quick comparison. Final dimensions, tolerances and grades are confirmed against your drawing or application before production.
Custom
Fused Quartz Technical Data
Engineers often ask what separates fused quartz from standard technical glass. The table summarises the typical physical properties of the transparent fused quartz we process, together with what each value means in real applications.
- Transparent quartz – maximum clarity for lamps, sight glasses, furnace tubes and optics.
- Opaque / milky quartz – diffuses infrared radiation; ideal for heat shields, flanges and insulating parts.
- High-purity sand – feedstock for quartz melting, crucible linings and precision casting.
| Property | Typical Value | Why It Matters |
|---|---|---|
| SiO₂ content | 99.9 – 99.99% | Low metallic impurities protect wafers, melts and samples from contamination. |
| Density | 2.20 g/cm³ | Lightweight compared with ceramics of similar size. |
| Softening point | ≈ 1683 °C | Defines the absolute upper limit before the part deforms. |
| Annealing point | ≈ 1215 °C | Temperature used to relieve internal stress after forming. |
| Strain point | ≈ 1120 °C | Below this, no new permanent stress forms during cooling. |
| Working temperature | 1100 °C / 1450 °C | Continuous vs. short-term use in furnaces and heaters. |
| Thermal expansion (20–300 °C) | 5.5 × 10⁻⁷ /°C | About 1/6 of borosilicate glass, the reason for outstanding thermal shock resistance. |
| Refractive index (589 nm) | 1.4585 | Stable optical behaviour for windows, slides and light guides. |
| Chemical resistance | Excellent | Inert to most acids except hydrofluoric and hot phosphoric acid. |
Values are typical for transparent fused quartz and are given for reference. Grade-specific data can be confirmed for your order on request.
Certificates & Credentials
Independent recognition of our quality system, technology level and on-site operations gives buyers confidence before the first sample ships.
ISO 9001Quality Management System
ISO 9001 Quality Management
Our quality management system has passed ISO 9001 certification, covering incoming material, production and final inspection.
HIGH-TECHJiangsu High Technology Enterprise
Jiangsu High-Tech Enterprise
Honoured by Jiangsu Province for our research and manufacturing capability in quartz materials and processing.
ONSITE CHECKVerified Supplier Premises
Onsite-Checked Supplier
Our premises and operations have passed an onsite check. Review our credit index and buyer reviews.
Payment Methods
T/T, L/C, PayPal, Cash
Delivery Terms
FOB, CFR, CIF, EXW, DDU, DAF, Express Delivery
Currencies
USD, EUR, AUD, HKD, CNY
Main Markets
North America, Eastern Asia, Eastern Europe, South America, Oceania
Buyer FAQ
Answers to the questions overseas buyers ask most often before placing a first order.
What is the difference between fused quartz and fused silica?
Fused quartz is melted from purified natural quartz crystal, while fused silica is usually synthesized from silicon-containing chemicals such as SiCl4. Fused quartz offers excellent thermal performance at a lower cost and suits most furnace, lighting and laboratory uses; synthetic fused silica is chosen when the deepest UV transmission and lowest metallic impurities are required.
What temperature can your quartz glass tubes withstand?
Our transparent fused quartz tubes are typically used continuously up to about 1100 °C and for short periods up to about 1450 °C. The softening point is approximately 1683 °C. Because the thermal expansion coefficient is only about 5.5 × 10⁻⁷/°C, the tubes tolerate rapid heating and cooling far better than borosilicate glass.
Can you manufacture custom quartz parts from my drawing?
Yes. We have more than 11 years of OEM experience and offer OEM, ODM and buyer-label services. Send your drawing, material grade and quantity to [email protected] and our engineers will confirm feasibility, tolerances and lead time.
Which payment and delivery terms do you accept?
We accept T/T, L/C, PayPal and cash, in USD, EUR, AUD, HKD or CNY. Delivery terms include FOB, CFR, CIF, EXW, DDU, DAF and express door-to-door delivery.
How do you pack fragile quartz glass for export?
Each item is individually protected with foam or bubble cushioning, tubes are separated so they cannot touch, and cartons are secured inside export-grade wooden cases for sea and air freight. Packing can be adapted to your warehouse handling requirements.
Which countries do you export to?
Between 71% and 80% of our output is exported. Our main markets are North America, Eastern Asia including South Korea, Southeast Asia, Europe, South America and Oceania.
Have a Drawing or Specification? Get Engineering Feedback Within One Hour.
Tell us the part, dimensions, quantity and operating temperature. Our team will recommend the right quartz grade, confirm tolerances and propose the most economical production route.
- Samples for evaluation
- Small batches accepted
- Buyer label available
Send Inquiry
Or email [email protected]